Comment 23 for bug 1892435

This double redirect issue also seems to be the cause of bug 1926797. It's another situation where we use encodeURIComponent to escape a request that needs to be redirected to Angular, which is escaped for a second time on certain servers by the 307 Redirect to the Angular locale path, and the decoded result ends up still being escaped.

Even if it's decided to use the new splash page, I think we might have to address the mod_rewrite inconsistency.