The docs mention [1] that go-neb can be used for notifications via Matrix.

However, go-neb has been discontinued, which its repo [2] mentions.

That same repo mentions matrix-hookshot [3] as the "spiritual successor", maybe that project could be listed alongside some instructions on how to use the Javascript transformation feature of matrix-hookshot to get well formatted alerts.

And of course go-neb should be de-listed now that it is discontinued.

[1] https://prometheus.io/docs/operating/integrations/#alertmanager-webhook-receiver
[2] https://github.com/matrix-org/go-neb
[3] https://github.com/matrix-org/matrix-hookshot