We have 3 closely identical tags: open-source, free-software and foss on PSE. These are almost identical other than for the philosophical "Open Source vs. Free Software" debate. Should these be merged or are these philosophical reasons enough to have them seperated?
When the philosophical differences come up in any sort of web forum, the result is usually flame wars with misinformation flying around, at least in my experience. We don't want that here.
There are definitions for "Free Software" and "Open Source" that are different from what the FSF and OSI define them as, but using them is just going to cause confusion, and confusion is likely to cause flame wars over definitions, according to what I've seen.
Therefore, there is no functional difference between "open source" and "free software", and we may as well merge the tags. Since the communities typically don't like to be confused, I'd keep "foss" and merge "open source" and "free software" into it.