Re: Needing to Find Out Functions Associated With Certain Actions
Instances of do_action() don’t, in themselves, do anything. They are signposts (‘hooks’, in WordPress terminology) that allow other plugins to add functionality. It is thanks to such idle hooks in WordPress that BuddyPress is able to function. See https://codex.wordpress.org/Plugin_API for more info about how the system works.
Grep will tell you the locations of all references to the text you provide. Generally, that will give you enough information to open up the file(s) given in the grep results and look at the specified line. I just ran the command I gave you above, and I got the following result:
In other words, as I suggested, this particular text is only mentioned in one place in BP – the moment where it is defined. The hook is not called by any function in BuddyPress.