Bug 11317 introduced in Koha 18.05 a new variable "access_dir" which is nowhere documented in the Koha manual, as far as I could see. In new Koha installations the following can be found in "koha-conf.xml" <access_dirs> <access_dir></access_dir> <access_dir></access_dir> </access_dirs> but it is nowhere explained how to set or how to use these veriables. In older versions of Koha that are updated these variables are missing and as far as I can remember there is no notice that they should/could be added. However, if you click Koha menu "Tools > Access files" you will get the message: Error: Files could not be found because the "access_dir" option was not set in "koha-conf.xml". Contact your system administrator to add this option. There is section https://koha-community.org/manual/20.11/en/html/tools.html#access-files in the manual but it just says "The directories where the files are stored need to be defined in the koha-conf.xml file." without further explanation.
The access_dir is used as the path or paths for the "Access file" tool, there is no other use I am aware of.
Would it make sense to hide "Tools > Access files" from the Tools main page, if the config is not activated? As it stands now, it looks like something was supposed to be shown there, but it is not shown because someone forgot to configure something.
I think it shows a hint on the missing configuration now on the page. I believe if you want to hide it, you could also not give the permission to users.