Does `info` (GNU texinfo 4.13) have a default search path for finding a `dir` file? Is it `/usr/share/info`? Even though I don't have an `INFOPATH` variable set in my environment, it seems to use the `dir` file in the path above. 

Relatedly, I have a script that sets up a directory with an alternate info directory structure. It does set a valid `INFOPATH` environment variable but `info` seems not to use it as invocation simply gives a blank screen without any menu items. 

Any guidance on how `info` progresses in searching the path?