Use maskable icons

https://css-tricks.com/maskable-icons-android-adaptive-icons-for-your-pwa/

we should also provide a maskable version of the aleksis icon

added part::frontend label

The aleksis icon has to be made looking something like this

(visit this link for a simple demo)

assigned to @yuha

The most interesting part here is probably how we convey such guidelines to administrators. Given that they can override the icons for their own instances, how do we ensure that they know how to follow the UI guidelines?

created merge request !936 (merged) to address this issue

mentioned in merge request !936 (merged)

closed with merge request !936 (merged)

mentioned in commit 9662f8cc