I found the following quote regarding Hookmark and iOS on another app forum.Just curious about when it was from.
The main feature is that it syncs Hook’s bookmarks from Mac (two way), if you enable iCloud sync on the Mac. Very handy to see links to anything there. E.g., you can click on a link to an email or Apple note and access it, assuming the message or note is reachable by Mail.app or Notes. Some of this requires installing a shortcut we provide. Due to iOS sandboxing, hook://file/ links are not yet synced.