Adding new property(read only) on the inspect tab inside the right panel

Hi community,

When I select a Text and then I want to have a new property on the inspect tab, inside the right panel. The idea is to transform ag to a different format and not write on the document itself.

For example:

ag = Label Head 1
newaG= labelHead1

This is possible to achieve?
If yes, can you tell me which API I should look for or give me an example?

Have a great day!
Best,
Jorge