folio-demo.gbv.de takes 50 seconds to load the first page

I agree, and I'll relay this to the accessibility SIG member.

For what its worth, the test I ran this morning in an incognito window has the JavaScript bundle downloaded in just under four seconds.

It looks as if this is caused by the throughput speed of the internet connection.
Enabling gzip compression has reduced the download time to 25%.
Speed tests from different locations result in page load times of 8 seconds or less for the first visit, following visits are much faster because of browser cache.
I close this issue because gzip compression reduced the priority and there isn't any other measure with resonable effort.

I've enabled gzip compression. This should reduce the download time of /bundle.a09a40df3c860c0b90b4.js to 25%.

The speed test at https://www.dotcom-tools.com/website-speed-test.aspx shows load times between 0.6 and 8 seconds.

Thanks for adding the extra debugging. I tried this morning in a new incognito window in Chrome (1323 UTC):

Safari on MacOS is showing the same network capacity issue (1330 UTC):

Oddly, a traceroute with a 1024 packet size doesn't show significant delays:

Thanks for the feedback, I see 127 seconds in the log at 16:01:46 +0100 = 15:01:46 GMT.

Other requests are much faster, see the last number showing the request-response-times.

Now I've enabled ip and browser name (http_user_agent) logging to see whether this only affects a few people (connectivity issue) or all.