From Tyler Hillsman on Mastodon:
Fairly late in the summer, but if this helps anyone, I just discovered a Tech Talk (not a WWDC session) that digs into migrating custom intents to App Intents. Very very useful and I feel silly for not knowing this was out there the whole time:
And:
TL;DW (but you really should watch if any of those words mean anything to you): keep matching var names and types, anything else can seemingly change.
View the post and watch the Tech Talk.