Test Payment Cards Extension per VasilyShelkov

Github: https://github.com/VasilyShelkov/test-payment-cards-extension

This extension allows developers using test payment cards from payment services to copy test card numbers to your clipboard. This will hopefully save you some time finding the test payment card in documentation.

Features:
- Currently only supports Stripe test cards but new payment services can be added on request.
- Allows favourite cards to be saved for future use.
- Shows the 3 most recently used cards from your previous sessions.