It is just a webkit wrapper. At least the last time I looked into it. UBlock Origin isn't possible. You can get some Apple sanctioned Ad-Blockers, but I think most (or all?) of them use a invisible VPN with DNS based ad blocking.
Mozilla has Firefox Focus for iOS, it does Ad Blocking but it's main selling point is No Tracking, No history and No synced bookmarks either
Mozilla has Firefox Focus for iOS, it does Ad Blocking but it's main selling point is No Tracking, No history and No synced bookmarks either