That was apparently added 8 years ago
i vaguely remember some old issue with appspot URLs that I had to work around
that appspot URL issue was probably that it required SNI for SSL, which was less supported then, and much more widely supported now, so I'm pretty sure this change is ok.
fixes #118. as far as we can tell, this is probably the root cause of a number of bugs filed against webmention.io over the last couple years, eg aaronpk/webmention.io#188, aaronpk/webmention.io#187, aaronpk/webmention.io#175, aaronpk/webmention.io#173, etc.
@aaronpk said:
that appspot URL issue was probably that it required SNI for SSL, which was less supported then, and much more widely supported now, so I'm pretty sure this change is ok.
cc @osak