(also) Stuck on “Loading Palette” Screen

There is an error, yet unrelated to e.trim (shown below).
Edge (v90) shows the same behavior, with the same console error (probably being based on Chromium?)
Firefox (v88) experiences the same loading freeze, yet with a slightly different error message (seems to be from the same origin, though).

Chrome log:

vendor.js:4 JQMIGRATE: Migrate is installed, version 3.3.0
DevTools failed to load SourceMap: Could not load content for http://127.0.0.1:1880/vendor/purify.min.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
red.min.js:16 Node-RED: 1.3.4
red.min.js:16 Versions
red.min.js:16 jQuery 3.5.1
red.min.js:16 jQuery UI 1.12.1
red.min.js:16 ACE 1.4.12
red.min.js:16 D3 3.0.3
red.min.js:16 Projects disabled
red.min.js:16 Uncaught TypeError: Cannot read property 'length' of undefined
    at Object.addNodeSet (red.min.js:16)
    at Object.setNodeList (red.min.js:16)
    at Object.success (red.min.js:16)
    at c (vendor.js:2)
    at Object.fireWith [as resolveWith] (vendor.js:2)
    at l (vendor.js:2)
    at XMLHttpRequest.<anonymous> (vendor.js:2)
addNodeSet @ red.min.js:16
setNodeList @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
(anonymous) @ red.min.js:16
i @ red.min.js:16
a @ red.min.js:16
i @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
(anonymous) @ red.min.js:16
(anonymous) @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
(anonymous) @ red.min.js:16
loadPluginCatalogs @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
t @ red.min.js:16
l @ red.min.js:16
(anonymous) @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
t @ red.min.js:16
success @ red.min.js:16
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
a @ red.min.js:16
init @ red.min.js:16
(anonymous) @ red.min.js:16
(anonymous) @ red.min.js:16
(anonymous) @ vendor.js:42
(anonymous) @ vendor.js:42
g @ vendor.js:42
success @ vendor.js:42
c @ vendor.js:2
fireWith @ vendor.js:2
l @ vendor.js:2
(anonymous) @ vendor.js:2
load (async)
send @ vendor.js:2
ajax @ vendor.js:2
s.ajax @ vendor.js:4
_fetchOne @ vendor.js:42
(anonymous) @ vendor.js:42
each @ vendor.js:2
(anonymous) @ vendor.js:42
each @ vendor.js:2
_fetch @ vendor.js:42
load @ vendor.js:42
g @ vendor.js:42
init @ red.min.js:16
init @ red.min.js:16
(anonymous) @ main.min.js:16
e @ vendor.js:2
t @ vendor.js:2
setTimeout (async)
(anonymous) @ vendor.js:2
c @ vendor.js:2
fireWith @ vendor.js:2
fire @ vendor.js:2
c @ vendor.js:2
fireWith @ vendor.js:2
ready @ vendor.js:2
B @ vendor.js:2

Firefox log:

Uncaught TypeError: e.types is undefined
    addNodeSet http://127.0.0.1:1880/red/red.min.js:16
    setNodeList http://127.0.0.1:1880/red/red.min.js:16
    success http://127.0.0.1:1880/red/red.min.js:16
    c http://127.0.0.1:1880/vendor/vendor.js:2
    fireWith http://127.0.0.1:1880/vendor/vendor.js:2
    l http://127.0.0.1:1880/vendor/vendor.js:2
    o http://127.0.0.1:1880/vendor/vendor.js:2
red.min.js:16:44964
    addNodeSet http://127.0.0.1:1880/red/red.min.js:16
    setNodeList http://127.0.0.1:1880/red/red.min.js:16
    success http://127.0.0.1:1880/red/red.min.js:16
    c http://127.0.0.1:1880/vendor/vendor.js:2
    fireWith http://127.0.0.1:1880/vendor/vendor.js:2
    l http://127.0.0.1:1880/vendor/vendor.js:2
    o http://127.0.0.1:1880/vendor/vendor.js:2