## [Specify `Accept` header in registration
request](https://github.com/ppy/osu/commit/28edb788f78723cda23281a8801acc2065592840)
The lack of it meant that in specific scenarios web would respond with a
chunk of HTML instead of JSON.
## [Allow showing registration error message even if no redirect is
given](https://github.com/ppy/osu/commit/6ad49941ffd7cdf662ccd404836bb52fccec2142)
There are scenarios where this can happen, and if it did, previously the
strict requirement to have both would cause the specific message to be
discarded and replaced with the generic "something happened" one.