System Information
Operating system: Darwin-17.7.0-x86_64-i386-64bit 64 Bits
Graphics card: NVIDIA GeForce GTX TITAN X OpenGL Engine NVIDIA Corporation 4.1 NVIDIA-10.33.0 387.10.10.10.40.133

Blender Version
Broken: version: 2.83 (sub 16), branch: master, commit date: 2020-05-12 22:10, hash: rB50ef801a79b5
Worked: 2.79

Short description of error
Any collections created with Ctrl-G aren't linked to the current scene by default. I've also found this to be the case just adding a collection through the Properties>Object>Collections>+ (Add to New collection) button as well as the default RigidBodyWorld and RigidBodyConstraint collections when adding these through the object menu, or through the Properties>Physics panel.

I can't imagine this is intended behaviour. The collections can be found in the 'Blender File' view in the outliner.

Exact steps for others to reproduce the error

1. Load default scene
2. Select default cube
3. Ctrl-G to add to new collection
4. Collection not shown in outliner>Scenes view, but visible in Properties>Object>Collections and Outliner>Blender File
5. Properties>Object>Collections>+ to add to new collection . Same result
6. Duplicate cube and select both
7. Object menu>Rigid Body>Add active (e.g.) = RigidBodyWorld Collection created but not in current scene
8. Object menu>Rigid Body>connect
9. Select created constraint-empty = RigidBodyConstraints Collection created but not in current scene.

Perhaps there are other situations where this might show up, but these are the ones I've found so far.

Thanks for looking!