Can I replace the "Edit this page" button with a custom button?

[Yura52]

UPDATE: created a new discussion instead: #731

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Hi! I would like to replace the "edit this page" button with a custom svg and a custom link. Is it possible?

P.S. If there is a way to simply add a new icon to the toolbar, I would also be very interested, but it seems that it is not currently possible.