There is really not that many places to look. I agree it could be better but part of the time the issue is with package maintainers. And to some extent, systemd has made things a little more convoluted. Compared to Windows it is far better because at least you don't go having to search thousands of registry keys.
>>encryp+(OP)
At least for the PATH, you can also automate the looking. When on a new POSIXy system, I usually try "(IFS=: ; ls $PATH)" at the shell to get a listing of all programs available.