Attempting to access Special:SpamRegex results in the message
You do not have permission to block spam phrases, for the following reason: The action you have requested is limited to users in the group: Staff.
Restriction to Staff may be by design, but it would be worth allowing at least administrators to see the regexes, at least to avoid conflicts with AbuseFilter.
Fair point, assigning to Jack who is far more knowledgeable on this particular extension for input.
Long story short, SpamRegex is intentionally very restricted because unlike AbuseFilter and whatnot, it is a global tool. If it were administrator-viewable (let alone editable!), that probably wouldn't go so well because all you need is a valid email address to create a new wiki.
Hub is a bit of a special case, as all Hub admins are directly appointed by staff, and thus are known to be trustworthy users. As such, we've decided to grant the spamregex user right to Hub admins only (in addition to staff).