USR-ZAR is a Gnome extension that displays the Dolar to Real currency. And all the values are getting from API AWESOMEAPI https://docs.awesomeapi.com.br. It is a fork of https://extensions.gnome.org/extension/5371/usd-bra/
Click on the green Code button above, the Download ZIP. Open a terminal and type the command gnome-extensions install Downloads/usd-zar.zip. On Wayland log out and in again, and on Xorg press Alt-F2, r to restart. Then turn USD-ZAR on in the Gnome Extensions app. Also try https://extensions.gnome.org/extension/1036/extensions/ to quickly enable and disable extensions.
