If it’s on Github doesn’t that make it OS?

No, when talking about open source software, people typically refer to a definition along the lines of the Open Source Initiative’s Open Source Definition. To distinguish this from software that you can only see the source (but don’t have rights to copy and modify it), they’ll use the term Source Available Software.

I don’t really know about the software you guys were talking about, but the repositories I looked at used the MIT license, which is OSI approved. However, that might not be all of the code they use. It’s not uncommon for a company to open source a “base” version, but they deploy a version that’s altered from that (I’ve got no clue whether they do or don’t).

People often use the OSI’s Open Source Definition when using the term “open source”. One of its criteria says “The license must allow modifications and derived works” which this license does not allow.

Is there a field in Tinder you can fill out with your job title?

Yes

And I’m asking how Tinder is verifying that.

They’re not. It’s fake

The reason they checked that it started with “Windows 9” was because it worked for “Windows 95” and “Windows 98”

Disturbingly, yes

Yeah, it’s like saying I can “compress” a png of the Mona Lisa to just the string “Mona Lisa” because I have a database of art.

You might want to check out microMathematics Plus. I last used it a few years ago. I remember being impressed by it, but thought it was way overkill for something I’d need on my phone.