I now have both polyfills in tampermonkey, but it doesn't work.
The console shows the following errors:
Beim Laden der PDF-Datei trat ein Fehler auf.
PDF.js v3.0.279 (build: d0823066c)
Message: Cannot read property 'length' of undefined
_otherError @ app.js:1099
_documentError @ app.js:1066
(anonymous) @ app.js:976
Promise.then (async)
(anonymous) @ app.js:975
Promise.then (async)
open @ app.js:958
webViewerInitialized @ app.js:2264
Promise.then (async)
run @ app.js:671
webViewerLoad @ viewer.js:246
viewer.html:1 Uncaught (in promise) UnknownErrorException {message: "Cannot read property 'length' of undefined", name: "UnknownErrorException", details: "TypeError: Cannot read property 'length' of undefined"}