eevee/floof — comment on commit 5543e5b85b52e86d2197815276b58a8b32c194a4
File: floof/templates/lib.mako line 13
By epii:

Woo, so it works like that.

On a more sober note, it is merely incidently never a valid email. I was mostly inclined to suggest it because it provides an actual MD5 hash (i.e. [0-9a-f]{40} ) although it appears that Gravatar merrily accepts most character strings and just spits out the default image. It is unclear whether there is a explicit guarantee anywhere of that remaining so, but it would be pretty absurd if the behaviour changed.

Of course, Gravatar also accepts the d=y flag to force it to always return the default image, and it accepts a zero-length string for the hash, so there may be an argument that the "cleanest" way to force the default image and be explicit about your intentions is something like:

https://secure.gravatar.com/avatar/?f=y&d=mm&s=foo

But whether that has any tangible advantage over just using "missing" as your "hash" is... pretty questionable.