Your hint “The restrictions at this node make a street inaccessible. Consider using oneway or access=no instead of restrictions” is misleading. One example: https://www.openstreetmap.org/relation/1130638 and https://www.openstreetmap.org/relation/1130639
Gaußweg is accessible by everyone (access=no is wrong). You can move in Gaußweg in both directions (oneway is wrong). Only entering Gaußweg from Adelbyer Kirchenweg is forbidden at this junction. Same applies for many other restrictions “that block access to a street”.
I fear that some mappers will delete correct turn restriction because of this hint and add plain wrong attributes to the ways. Maybe a hint like “please check if there’s a oneway restriction or another access restriction” will be a better choice.
I’ve seen it multiple times that main streets in Berlin were blocked due to wrongly set restrictions, which caused major problems in routing. That’s why I’m quite sensitive about those and the main reason I developed the tool. Thanks to your example I learned that there can be exceptions. I’m going to fit the text accordingly, however I trust mappers that they’re careful when making such changes.
The colors are described in the “About” section on the page. Apart from that, complete arrows mean it’s a one way street. Arrows on only one side of green/red lines mean it’s a two way street, where the restriction only affects the shown direction.