CustomTrack recording's gone.

Yes, in 2019.2 any 'recordable' properties show up automatically in curves windows and the curves can be edited directly. Keyframing has been removed in favor of curve editing.

 

You will need to set it manually on the curve (double click to add a key, and right click and select Edit Value... to explicitly set it). If you right click the the property in the inspector, there is an AddKey method that should let you record the keyframe, but that functionality appears to have regressed.

We will try to get a fix for that asap.