There are lots of requests for this in these discussions.
On desktop it’s fairly simple to swap a watermark.png and tweak interface_config.js etc. and get a reasonable result without having to delve into any serious code, but for the apps (both Android and iPhone) it’s a very different story.
Suppose we define a unique directory location on a jitsi server that can (only) contain custom “theme” materials - maybe you’d want a logo image, a background image and a primary/secondary colour defined here? (Obviously you could cater for many more options with this approach but let’s keep this simple - most people just want some personal branding).
When a desktop or app connects to any Jitsi server it looks at this location and uses content if it exists, or runs with the defaults if not. This could work with both desktop and apps. And a “powered by Jitsi” graphic could be added when a custom theme is detected so as to maintain the accreditation etc?
I’m sure others can suggest improvements to this, but the approach of making these elements “external” would facilitate branding. Or perhaps the idea is to make this harder so the Jitsi brand gets most exposure! ???