Kind of, anything in permited_uri_chars is allowed. This includes spaces, slashes, commas, %, and a handful of others by default. As I said only skimmed quickly

Kind of, anything in permited_uri_chars is allowed. This includes spaces, slashes, commas, %, and a handful of others by default. As I said only skimmed quickly so maybe I'm missing it. Will take a deeper look in a bit once not on mobile.