Hi there I am Arya , gsoc aspirant pursuing Btech. in computer science

I am interested in project Replacement of deprecated Gtk classes @rodolforg do you any suggestion for me

Hello @arya. Welcome.

First of all, read these guidelines:

After that, you could try some of Good First Issues to be used to Synfig code, community
and workflow.

Regarding the project idea itself, take a look at files related to menu actions (like synfig-studio/src/gui/app.cpp).