Blur a part of pano (rect area)

I just added it to zfilter
https://krpano.com/plugins/userplugins/zfilter
(docu update coming)

yes ... background blur, brightness, contrast, saturation, hue, sepia

the plugin page is not updated yet, that maybe needs time, because i want to change from shareit to gumroad.
but it works the same as the normal layer/hotspot filters.

https://imgur.com/a/zQTauBz

<action name="init" autorun="onstart">
	addzfilter(layer[skin_controlbar_bg]);
	set(layer[skin_controlbar_bg].bgblur, 10);
</action>

fyi: background filters still do not work in firefox. in general. also your example won't work there.
in firefox this it is still under experimental, they hopefully enable it in one of the future versions.