Bake master comp (motion graphics template, essential graphics panel)
Currently, when using master properties within After Effects there's no easy way to "go back" to a regular tree of comp and pre-comps without losing the custom values applied to each instance of the master comp.
Right-click menu to duplicate a comp that has been customized using master properties.
This would create duplicates of the selected master comp and all of its children/pre-comps with the custom master properties values applied to the appropriate source properties within those duplicates.
In short, something like True Comp Duplicator, but compatible with master comps: https://aescripts.com/true-comp-duplicator/
Expressions used inside the master comp and its children should be updated to the duplicated comp hierarchy.
If this can't be done, please at least give us scripting access to push/pull via Property method and/or source/path of a master property via Property attribute:
Ole Kristensen commented
Yep - The only thing needed to script this would be the ability to get to the source property in a master comp from it's master properties when used as layer.
thisComp.layer("Fancy sign").masterProperty("Title Text").source;
thisComp.layer("Fancy sign").masterProperty("Fancy Slider").source;
Should be able to return a reference akin to:
comp("Fancy Sign").layer("CONTROLS").effect("Fancy Slider")("Slider")