I'm not entirely sure what this is, but those screenshots do the absolute opposite of selling it.
The "fyne" framework is a Go UI toolkit, in a similar vein to Qt or GTK. It leverages Go's cross-compilation to compile for various architectures, and has built in utilities for publishing for the iOS/Android app stores.
This appears to be a desktop environment based on the UI toolkit.
*Disclaimer: Interpretation based on 5 minutes of skimming docs
Which is totally my fault, for sure, not theirs in the slightest. It’s just…that ugly.
I looked and it is decent, but needs polish. Which it will get unless broken people keep shitting on it.