What happened to the brasero?

We removed Brasero from the OS in 5.1.0. See this section of the release notes for why, and some suggested alternatives.

I searched our forum and found this thread where another user has had some success using wodim on the command line:

Someone in the GNOME community has done most of the necessary work to publish Brasero on Flathub so in principle you can build a Flatpak from there.