By survey, the TM-CLK Highway terminates as currently mapped (right outside the HK-ZH-MO bridge clearance building).

To elaborate on my Route3/Route9 point, observe that Tsing Long Highway is constructed in a way that makes one think it is "intended" to go north towards Route 9. Then, observe here that the Tunnel similarly is constructed in a way that makes one think it is "intended" to go to the Airport. The road towards Airport is one whole structure with a median; that's a clear indication it's the "main path". 

Also consider other peripheral hints. The namesake of the project hints that the Tunnel is intended to connect to Airport. The path towards airport is almost capable of supporting 3 lanes.

Contrast with Route2/Route4 where no such "main path" exists, and also Route3/Route4 where the supposed "main path" quickly splits into many obvious `_link`s.

Ultimately, the goals of the changeset:
- highlight the main path (ie `motoway_link` becomes `motorway`)
- correctly indicate tunnel area (ie everything else becomes `primary/_link`)