The problem with inserting Cyrillic characters from the clipboard

[Divanovi4]

If you cut or copy text to the clipboard, for example:
dssdgsdgdssdgяячячпыввыпвы
then, when it is subsequently inserted, the text takes the following format:
dssdgsdgdssdg\u044f\u044f\u0447\u044f\u0447\u043f\u044b\u0432\u0432\u044b\u043f\u0432\u044b

To reproduce. Steps to reproduce the behavior:
Server start command:

xpra start :10 --bind-tcp=0.0.0.0:9876 --exit-with-children=yes --start-child="mousepad" --html=on \
   --encodings=no-rgb24,no-rgb32 --video=no --min-quality=60 --bell=no --mdns=no --speaker=no \
   --pulseaudio=no --audio=no --speaker=off --notifications=yes --webcam=no --microphone=off --av-sync=no \
   --opengl=no --daemon=no --clipboard=yes --clipboard-direction=both --remote-logging=no \
   --keyboard-backend=ibus --keyboard-layout=ru --keyboard-variant=nodeadkeys

config content /etc/xpra/html5-client/default-settings.txt

keyboard_layout = us
blocked-hosts = xpra.org,www.xpra.org
min-quality = 10
min-speed = 50

System Information
Server OS: Debian 12 Bookworm
Client OS: Windows 10 22H2
Xpra Server Version: 6.3 r37394
Client Browser: Brave 1.75.178

[totaam]

--speaker=no --pulseaudio=no --audio=no --speaker=off

Same as just --audio=no.

--clipboard=yes --clipboard-direction=both

This is the default and therefore does nothing.

Can you enable clipboard debugging from the connect dialog and post the javascript console events when you copy?

It looks like we may need to unescape the clipboard data, but I'm not sure which even is firing with your browser / OS / network combination.