According to tag excerpt of documentation:
For questions regarding written documentation such as manuals, help files, policies, instructions, or guides.
But there exists helpfile too which in my opinion can be considered as the synonym of documentation since I think helpfile is in documentation only.
But if the community wants to keep the tags separate, please consider posting an answer to this question with details.
helpfile, it seems to be incorrectly used. They should be retagged first, as the tag is being used to "request for help". For example, askubuntu.com/q/537979/8698 and askubuntu.com/q/596355/8698 anx there are a lot more as well.