[michaelmior]

They do mention an alternative where you can set stuff in the query string. I'd probably rather do that instead. Especially since you could easily end up putting that button out of the context of your repo at some point and have it end up completely broken.

[cben]

But if I fork a repo with a button (or even navigate to different branch/commit in same repo), a manually set query string would still point to the same code. Whereas the referer headear can identify exactly the right version briliantly.