How to invoke an application in "Freeform Mode" via ADB?

##### Question If I enable adb shell settings put global enable_freeform_support 1, how can I launch an activity in Freeform Mode (presumably, with am), like I can from com.android.quickstep.RecentsActivity? ##### Context I know that it's possible, because when diagnosing issuetracker.google.com/issues/423197817 , I noticed that if I closed cmd activity start --user 0 -a android.intent.action.VIEW -n com.android.wallpaper/com.android.customization.picker.CustomizationPickerActivity -f 0 com.android.wallpaper whilst it was in Freeform Mode, when I launched it from com.android.settings's GUI (as cmd activity start --user 0 -a android.intent.action.VIEW -n com.android.settings/com.android.settings.wallpaper.StyleSuggestionActivity -f 0 com.android.settings ), it re-launched in that mode.