packages.debian.org is frequently unavailable (503 Service Unavailable)

When accessing a page for a package, e.g.
https://packages.debian.org/source/stable-backports/firmware-nonfree
it is frequently slow or fails.

It's possibly caused by a VPN block or rate limiter, but if that's the
case, these are static pages so why is it necessary to rate limit them
in the first place?


Example:
---
Service Unavailable
The server is temporarily unable to service your request due to
maintenance downtime or capacity problems. Please try again later.
________________________________
Apache Server at packages.debian.org Port 443
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