You might want to have a look at Sourcehut (https://sourcehut.org/ https://sourcehut.org/). If I recall correctly they support e-mail-only workflows, which mean

You might want to have a look at Sourcehut (https://sourcehut.org/ https://sourcehut.org/). If I recall correctly they support e-mail-only workflows, which means you can contribute by sending patches. I haven't used it myself so far. As far as I know Sourcehut has been designed with the e-mail based wokflow used by the Linux kernel community in mind.