texdoc
texdoc need a tlpdb database.
Download
it
to ~/.local/share/texmf/texdoc/Data.tlpdb.lua.
Then create ~/.local/share/texmf/texdoc/texdoc.cnf:
texlive_tlpdb = /home/user_name/.local/share/texmf/texdoc/Data.tlpdb.lua
Now it can work:
$ texdoc impatient You don't appear to have any local documentation installed. There may be online documentation available for "impatient" at https://texdoc.org/serve/impatient/0 This documentation may be for a different version than you have installed. Would you like to search online? (y/N) y
https://texdoc.org/serve/impatient/0 is opened.