IDC: Check `host` without being capitalization specific?

When the `host` portion of the URLs mismatch, do we need to throw the IDC prompt? Does anything break for failing to match the case of the `host` portion of the URL?

Would need to verify the signature isn't impacted.

Assuming nothing breaks, we should be less strict about case.

Start by locating the IDC prompt's host comparison and the signature verification path. Check whether host casing affects URL signatures; done means confirming compatibility and defining a case-insensitive comparison without breaking verification.

Written by the indexing model from the issue text.