The addon is named B-Rename (Bake renamer).

This addon will help you to speed up renaming objects to prepare for baking. It lets to append names of the collections to the objects names (as suffix). In general you can rename any objects (any types) like meshes, curves, lights, cameras, bones... e.t.c

How it works?
 
For example, you created two different collections on top level (Scene collection).
And you named the first collection _HIGH and the second one _LOW.

After that you create two different objects Cube, and Cube.001 =).
First Object (Cube) you put in the _HIGH collection.
And the second (Cube.001) in the _LOW.

Now the objects are in differents collections _HIGH, and _LOW.

The next step is renaming.

You have to select both objects (Cube and Cube.001) in viewport or in outliner.

After selection you have to press hotkey combination - Ctrl+Shift+F2 (or the one you've set up in the Preferences).

Then you will see a small modal window with several lines.

The first line is a reminder what to do if you want to append collections names to the existing object's names.
Use text input field to enter new name for the selected objects. Enter '*' (an asterisk) to leave existing objects names and just append collections names as suffixes.

The third line (Generated name) is only informative. It will give you a hint on how the active object will be named after renaming.

The fourth line (a warning) will appear only if after renaming some objects may receive identical names (i.e. they belong to the same collections) so Blender will automatically append .001, .002 and so on for them.

How it works?

After entering the desired new name in New name field.
In our case i changed the old name to the new - test.
You have to press the enter on your keyboard once.

After that in Generated name field you will see a new generated name for the
active object (the last selected with orange highlight). You can return to the new name field if you don't like the result and want to change something.

Finaly just press Enter again. That's it! Now you have two objects named test_HIGH, and test_LOW

This is a very small and simple overview for this addon. We recommend you to watch the video overview.

https://www.youtube.com/watch?v=0W2nVIV9Hps&feature=youtu.be