fapchat2 "Many programs (the binaries/scripts) end up in /bin or /usr/bin with other parts in various configuration directories (often in/under etc) as you already noted.

For any specific command you can checkout whereis

whereis prog_name

and it will give you some information about where this command is to be found. You can also try which

which prog_name

Also, this graphic and explanation/examples might be helpful." (Source - Superuser.com)

In this case running the command to "find" Firefox and Chrome would look as follows:

scott@solus ~ $ whereis firefox
firefox: /usr/bin/firefox /usr/lib64/firefox

scott@solus ~ $ whereis google-chrome
google-chrome: /usr/share/man/man1/google-chrome.1.gz

Hope that helps! And remember Google/DuckDuckGo/etc is your friend, cheers!

    Are talking about these?

    They are saved in /usr/share/applications/.

    If you want to modify them use menulibre.
    sudo eopkg it menulibre
    After installing you can find it on menu "Menu Editor"

    After being modified the output with be at ~/.local/share/applications/
    with a name like xxxx.desktop.

    fapchat2 i guess you are talking about downloaded files ...if yes it will be in Downloads directory by default...or you can set the download directory it in Preference/Setting in the browser...or you can enable Always ask you where to save files

        Do you mean the location of downloaded packages for install?
        I don't understand... Can you explain please?

        Linux is not windows. Binaries (=executable files) go in standard locations.
        You'll find most of them in /usr/bin, a few go in /bin. The ones that require elevated privileges go in /usr/sbin or in /sbin.
        So if you really don't want to use a terminal (which it the convenient way for such things, as a lambda user who doesn't use the terminal shouldn't care where the files are installed), just open Files and browse these folders and look for filenames that look like what you want (double-click them to execute them and see if it is what you are looking for).

        But just the hard way to do things and less reliable than commands that can return you the info immediately.

        fapchat2 All those listed from 3rd party repos...(Normally check update return noting I never had any success with that )...better you download latest from source/3rd party website and install in /opt

        for example goto ~/Downloads in terminal and
        tar -xf <fileName>.tar -C /opt don't forget to copy *.desktop files to ~/.local/share/applications/

        from solus repo you can search package in Dev Tracker for example

        https://dev.getsol.us/source/firefox/ and installing location details click on pspec_x86_64.xml
        and the software's original location under source : in package.yml (i guess this is the one you are interested in)

        if you wanna try in terminal

        eopkg info -f firefox

        If possible watch Josh's solus packaging video it will be helpful.