This answer aims to present reasoning for the above mentioned checklist and keeping edited versions of questions which mention non-Ubuntu distributions, but in fact are asking about non-Ubuntu specific issues. Key points presented:
- Restricting scope to Ubuntu only questions is very difficult, since Ubuntu userland shares the utilities with other distributions
- Keeping such questions does not harm the site, and in fact benefits the site and community
- Many fears related to disallowing editing and keeping such questions are based on either fallacies or wrong assumptions
### Operating Systems and Distributions
Understanding where Ubuntu stands within Linux and Operating Systems ecosystem might be beneficial to understand the reasoning presented in this post. To quote Wikipedia (with my emphasis)
> A Linux distribution (often abbreviated as distro) is an operating system made from a **software collection**, which is based upon the **Linux kernel** and, often, a **package management system**.
Ubuntu in itself is a Linux distribution and by that definition is a collection of software, and much of the software is distribution agnostic. To quote [lesmana's answer][1]:
> Ubuntu is a distribution which packs a lot of software together, small and large. There are graphic drivers, the X server, and Gnome, among others. **Ubuntu itself is not developing those software**. Ubuntu is "just" packing the software together, making sure that the individual components work together. All that software which Ubuntu is packing together are called upstream from Ubuntu's point of view.
In particular much of the userspace utilities which Ubuntu packages and distributes can be found on other Linux distributions and operating systems:
- GNU coreutils - can be found virtually on any Linux distribution. This includes utilities such as `ls`, `df`, `du` and so forth.
- `bash` and `dash` shells. Tangentially, of particular importance is the use of these two as POSIX-compliant `/bin/sh`. While currently `dash` is symlinked to `/bin/sh`, at one point in time Ubuntu used to have `/bin/bash` as POSIX compliant shell, just as CentOS or RHEL. This has been greatly covered in [Gille's excellent answer][2].
- GNOME desktop
- X11 server
- systemd init system
- Non-shell scripting languages: Python, Perl, `awk`, `sed`, `grep`.
In other words, Ubuntu's inclusion of these tools does not make use of these tools exclusive to Ubuntu, nor encountering issues with these tools outside of Ubuntu environment make the issue non-existent or non-applicable to Ubuntu. Even more so, some of these utilities are essential to Ubuntu's functionality. Booting the OS involves `grub`. Administering the system requires a shell, and preferably POSIX-compliant shell; this becomes significant in enterprise environment where system administrator has to support multiple operating systems or distributions.
While Ubuntu has been keen over the years to create a usable and user-friendly desktop distribution, Ubuntu is a significant player in server market. Just to quote [Datanyze page][3], Ubuntu has 26.83% market share compared to CentOS with 19.9%. Therefore, addressing questions related to utilities which Ubuntu uses is critical.
Now, of course Linux distributions share utilities, however by virtue of POSIX standard, in order to be UNIX-like operating systems have to conform to base set of specifications. For instance [macOS is POSIX compliant][4] and provides basic set of utilities along with `bash` shell. Now, admittedly there are differences in flags which these utilities may use, however asking a question about `bash`, or `ls`, or `du` does not make it exclusive to Ubuntu or MacOS unless it touches on the specific flags.
Of course, there are overt cases where the issue touches on specifics of the OS or utilities. For instance, if a question touches on [`/usr/bin/xpg4` directory][5] - this is something that is supported on Solaris, HP-UX, and a few others, but not Ubuntu. [On macOS X user's home directory][6] is located in `/Users` and not `/home` as on Ubuntu. In such cases the question does have exclusivity to the OS.
Please note that in the age of search engines, there's no requirement to be aware of these differences. If you suspect this seems to not apply to Ubuntu, one can always search and verify. Senior users who have worked with other OS or distributions know these simply by virtue of experience and research, which other users can perform as well.
Considering other software, such as GNOME desktop or X11 utilities, the key point to note is that they have common utilities and common interface. Just as a script written for `/bin/dash` operates on premise of writing POSIX compliant code, so do solutions to issues involving these should be addressed - by addressing common interface and common utilities.
Of course, there are exceptions. Linux kernel being a common denominator for distributions, is not always the same. [Linux Insider](https://linuxinsider.com/story/85050.html) cites case where 4.13 kernel shipped with Ubuntu 17.10 had unfinished kernel module for SPI devices which did not affect Arch Linux or openSUSE with the same kernel version. As such, the low-level software which has direct influence from Ubuntu developers and maintainers does make this case exclusive. And yet, software which does not touch low level computing , such as `bash` or core utilities, are well applicable to both Arch and Ubuntu, for instance.
### Code of Conduct
Ask Ubuntu, [despite being featured on Canonical's site and installer][7], is not an official tech support. We are community and not Canonical employees, although some of the Canonical employees do participate here. As such we are not bound by exclusivity. Rather, I propose to focus on inclusive treatment of good questions and answer. To cite Stack Overflow code of conduct (and to keep our community grounded in the fact that we are part of Stack Exchange network), here's the expectations:
> If you’re here to help others, be patient and welcoming. Learning how
> to participate in our community can be hard. Offer support if you see
> someone struggling or otherwise in need of help.
>
> Be kind and friendly. Avoid sarcasm and be careful with jokes — tone
> is hard to decipher online. If a situation makes it hard to be
> friendly, stop participating and move on
Without naming names, there have been cases where mentions of other distros got terse comments, which are unwarranted. In fact, such behavior has been detrimental to Stack Overflow, as they'e realized, and it can be detrimental to our community. Terse behavior has much more negative impact than integrating a question which mentions non-Ubuntu distro.
To quote [Ubuntu Code of Conduct v2.0][8] (with my emphasis):
> We want a productive, happy and agile community that can welcome new
> ideas in a complex field, improve every process every year, and **foster
> collaboration** between groups with very different needs, interests and
> skills.
>
> We gain strength from diversity, and **actively seek participation from
> those who enhance it**. This code of conduct exists to ensure that
> diverse groups collaborate to **mutual advantage and enjoyment**. We will
> challenge prejudice that could jeopardise the participation of any
> person in the project.
Integrating questions that may mention but are not specific to non-Ubuntu distribution aligns with Ubuntu code of conduct. It fosters collaboration, which is beneficial to both Ask Ubuntu to gain a question and more answers, and the person and community to which they may belong. It is a win win for both, mutual advantage and enjoyment. Another quote:
> Open meritocracy
>
> We invite anybody, from any company, to participate
> in any aspect of the project. Our community is open, and any
> responsibility can be carried by any contributor who demonstrates the
> required capacity and competence.
Ubuntu code of conduct itself is welcoming to participation in any aspect of the project. As such, questions which may be solved with Ubuntu tools do in fact foster participation in the project: answers gained from such question will be applicable and useful within Ubuntu environment.
Let me remind you also that according to the rules for moderator elections, [moderators are required to sign Ubuntu Code of Conduct][9]. So bringing up these quotes is not something out of thin air. Our community does fall under this code of conduct by virtue of our moderators being required to follow it, and therefore enforce it.
Note, however, that what I've addressed in "Fears" section are often claims that do attack opinion of higher reputation users who do propose inclusion of questions that mention non-Ubuntu distributions, who are also under exactly the same code of conduct. It is my personal view that very valid opinions (which are based on experience) regarding such question are often met with distrust, which goes against both codes of conduct mentioned here.
### Recent example of poor practice
Here's an overview of how recently asked question has been handled: a user asked [Is there a way to create a key binding that would allow me to mount my googledrive? \[duplicate\]][10], which has been voted to be closed, subsequently reopened (note, both actions by community vote), then subsequently another question[How do I create a key binding that allows me to mount my google drive?][11] has been asked and original merged and closed as duplicate of new one.
Key things to note:
- asking a new question has not any shape or form contributed to the question being Ubuntu-specific. In fact, information is essentially the same.
- comments which in respectful manner addressed the user and notified that we only are able to address Ubuntu side of things have been deleted.
- community vote to reopen has been essentially ignored, showing certain degree of distrust
Additionally, if we were to use this as precedent, consider OP reaction. Your question is closed, but exactly same one appears from another user under the premise that this is specific to Ubuntu, while original question is not despite them being exactly the same. It may show favoritism to existing community members and ignoring the issue in favor of internal policy/politics. Of course, let's remember that moderators should step in when issues arise, but this particular case could have been handled with community vote and more trust to the members.
### Fears
There are persistent fears within community, which often are on the verge of emotional investment rather than practical and professional view on the issue, and often base the claims on [slippery slope falacy][12]. I will address these issues without naming names, since it's we need to distinguish between the message and the messenger, many of whom I greatly respect and consider friends.
1. **It's policy making.** It is not policy making as in making it official and written on [Ask Ubuntu Help page][13]. Rather, we're addressing self-moderation of the site, with opinions and discussions presented by users to have a valid reason for questions to stay on the site. These issues should not be addressed by the moderators on an on-going basis, but by the community, and the community should agree on set of practices.
2. **Only high reputation users do this**. To quote [theory of moderation][14]:
> Users with 15 rep can flag posts.
>
> Users with 500 rep can review posts from new users.
>
> Users with 2,000 rep can edit any question or answer in the system.
>
> Users with 3,000 rep can cast close and open votes.
>
> Users with 10,000 rep can cast delete and undelete votes on questions,
> and have access to a moderation dashboard.
>
> Users with 15,000 rep can protect posts.
>
> Users with 20,000 rep can cast delete votes on negatively voted
> answers.
As you can see at 500 and 2000 users already can review or edit posts. The claim that it is an exclusive view or ability of high-reputation user is not supported by the factual ability of lower rep users to participate in editing. Note also that reputation does not reflect experience in the matter itself - a system administrator with 10 years of professional experience may as well sign up for this site, and remain on low reputation. It does not diminish her knowledge in the matter, nor cognitive abilities to distinguish whether or not an issue is distro-neutral. The fact that high reputation users have been addressing this issue is that higher reputation tends to coincide with higher involvement into the community, and tangentially experience with handling questions that may require distinguishing whether or not an issue can be addressed within this community.
3. **This sets precedent for non-Ubuntu users asking questions**. Let's address the elephant in the room that this most often cited reason is slippery slope fallacy. Practically speaking, [existing guidelines][13] do not in any shape or form prevent posting a question in "action-taking" sense of it. Questions *are* being asked already mentioning non-Ubuntu distributions. They are, however, left up to the community to moderate. It is up to us as community to determine the value of the question.
The underlying fear is that the site will be overrun by non-Ubuntu questions. However, at the time of writing there are plenty of question which are non-Ubuntu specific simply by virtue of utilities involved being non-Ubuntu specific. At the time of writing, there are the following amount of questions with these [tags][15]:
- command-line, 16327
- partitioning, 9577
- bash, 7414
- networking, 16098
- nvidia, 8300
- permissions, 5355
- ssh, 4314
- python, 3592
Many of these have been asked before on other sites or have similar answers, which does not imply they should be moved elsewhere. I myself have addressed [How do inode numbers from ls -i relate to inodes on disk][16] of Unix & Linux, using very much same information as in [What are directories, if everything on Linux is a file?][17] on Ask Ubuntu. Imagine if the later one started out saying "Hi, I'm using Debian". It's an irrelevant information to the core of the issue, [just like emojis are][18]: "...if something isn't adding relevant information to a post, it is noise and it is better to remove it."
4. **There are other support communities and we're robbing them away from questions**. Quite the opposite: Ask Ubuntu often integrates solutions from other communities, and vice versa. Example: [/r/linuxquestions makes use of askubuntu solutions][19]. [My Ask Ubuntu answer][20] integrates a step by step solution on linuxquestions.org into a script. Solutions being publicly available provides the chance for solutions to spread, and in no way robs other communities of questions. As a matter of fact, they spread to other communities.
5. **There's often no way to know if a question's answers will be Ubuntu-specific, Mint-specific, or otherwise**. Users on this site are only required to answer in Ubuntu-specific manner. Where an issue does not touch on kernel internals, package manager specifics, or OS-specific directory and filesystem issues, they are perfectly applicable to Ubuntu. Again, what is being missed quite often is that the underlying premise of a question being Ubuntu-specific is wrong - many utilities are in no shape or form Ubuntu specific.
6. **Ask Ubuntu will pose as authority for Debian and Ubuntu based distros**. Sadly, it will not, simply by definition of this site being specific to Ubuntu. We have no control over Linux Mint development, package management, kernel specifics. We do, however, **share** utilities, and addressing issues related to that in no way exerts authority over other communities. In fact, it only helps both to find a solution to the actual problem.
7. **Letting people ask questions which mention non-Ubuntu distro detracts from quality**. In cases where an issue can be handled via common interface/utility, quality of the post resides within the question and answer itself, not within mentioning or omitting of distro. Full disclosure: I have been Deepin Linux user for the past two years. In corse of this time, I have posted the following:
- [What are directories, if everything on Linux is a file?][17]
- [How to get a process exit status from another shell session?][21]
- [Why does ls color two supposedly similar files differently?][22]
and many answers which were written on my distribution. Judging by progressive increase in my reputation on recent answers, they have been found useful and relevant to Ubuntu community, simply by virtue of not being specific to Ubuntu, but using common tools. Their quality, if I may say so, does not pale compared to someone who runs exclusively Ubuntu.
### Conclusion
The ultimate goal is to make the site and community better. While there are certain questions which do not belong here, many of questions which are otherwise closed could thrive and receive a proper answer here just as well as anyone coming and saying "Yes, yes, I run Ubuntu" - something which we can only verify by questioning the user, where as it is much better for users themselves to admit what distribution or OS.
Ultimately, we are not required to support any other distro besides Ubuntu and it is not what is being asked here. What is asked is discretion and focus on inclusion of questions *for the benefit of the site*, and tangentially the users who ask those questions. Fact remains that a lot of userspace is not Ubuntu specific.
It's also not a policy, but a proposal for our community to address these questions with a more practical and consistent approach, rather than mechanical parroting of "This is not about Ubuntu". Again, note that the checklist does not require anyone to be an expert in other distributions, because questions related to common interfaces and utilites are not specific to those distributions just as they are not specific to Ubuntu. Everyone retains their right to vote, everyone retains their right to edit questions, and there are no new rules that bind users. By contrast, adopting such checklist as practice should make it much easier for reviewers and editors to determine whether or not a question is off-topic: no common interface or utilities ? off-topic. Has common common interface and utilities ? On-topic.
Finally, please consider Raphael Hertzog's comment (Debian developer) on [How is Ubuntu different from Debian][23]:
> Debian is the result of the work of its contributors... bring us the nice improvements and more people can eat at the Debian restaurant too. It's not the end of the Ubuntu restaurant. Together we will be stronger and maybe more people will eat sanely (and maybe the number of fast food will drop).
Ubuntu is also result of contributors - all of us, each one writing questions, editing posts, posting answers. A question solved is another contribution. Maybe a minor one, but one that is publicly available. Where we can recognize unifying factors (in the form of userland utilities at least), and where we can address issues related to those, we obtain Unity and not just as in desktop name. More importantly, we should thrive to focus on the values outlined in Ubuntu Code of Conduct and be welcoming of people.
***
### Addendums
To quote [an answer][24] by our esteemed moderator Oli on the same topic:
> You can —and people have tried to— make the argument that we should
> only handle things that are "strictly Ubuntu". What is that though?
> What is Ubuntu specific? Ubuntu is a collection of other people's
> tools so ultimately, very, very few things are actually specific to
> Ubuntu.
>
> Sidestep the madness that comes from prescribing a strict "line"
> around on-topic subjects. It's folly to try. We aim help people
> install, use and develop on Ubuntu. It's that simple.
>
> Please don't chase questions around with pitchforks because the
> underlying software also exists on another platform. The same can be
> said for 99% of the software available in Ubuntu.
[1]: https://superuser.com/a/269958/418028
[2]: https://askubuntu.com/a/976504/295286
[3]: https://www.datanyze.com/market-share/operating-systems/ubuntu-vs-centos
[4]: https://unix.stackexchange.com/a/423123/85039
[5]: https://unix.stackexchange.com/a/199255/85039
[6]: https://apple.stackexchange.com/a/51317/297223
[7]: https://meta.askubuntu.com/q/2998/295286
[8]: https://www.ubuntu.com/community/code-of-conduct
[9]: https://askubuntu.com/election/5
[10]: https://askubuntu.com/q/1115059/295286
[11]: https://askubuntu.com/q/1115520/295286
[12]: https://en.wikipedia.org/wiki/Slippery_slope
[13]: https://askubuntu.com/help/on-topic
[14]: https://stackoverflow.blog/2009/05/18/a-theory-of-moderation/
[15]: https://askubuntu.com/tags
[16]: https://unix.stackexchange.com/a/498504/85039
[17]: https://askubuntu.com/q/1073802/295286
[18]: https://meta.askubuntu.com/a/18354/295286
[19]: https://www.reddit.com/r/linuxquestions/comments/5zl0qk/ubuntu_1604_installation_error/
[20]: https://askubuntu.com/a/1043139/295286
[21]: https://askubuntu.com/questions/1071821/how-to-get-a-process-exit-status-from-another-shell-session
[22]: https://askubuntu.com/q/1112126/295286
[23]: https://askubuntu.com/questions/1336/how-is-ubuntu-different-from-debian#comment1371_1358
[24]: https://meta.askubuntu.com/a/14664/295286