autolinking is not working for abasurl as it contains not url conform characters so you would still have to link it manually but it is not sanitized anymore.
Addressing feature: Custom URL Schemes autolinked #3218
Create a custom SafeAttrValue function which can allow non-standard protocols such as thunderlink: cbthunderlink: and aodroplink: to operate correctly without getting the value stripped away. Any other protocols and code remain to be processed by the default safeAttrValue routine.