Guide layers and adjustment layers are "special" and work differently to other layers in a timeline.
Can we please have a method to differentiate them that's more visible than just using label colors.
The AE interface used to show reversed layers with red stripes through them, so presumably the interface code is able to add some degree of textures to layers in the timeline.
Even something as simple as a grid, or checkerboard pattern (that works with the label color) would be useful to instantly identify guide layers and adjustment layers in a composition.
I have attached a crude mockup but it's really just a conversation starter.