System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2080 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89
keyboard german, display language english

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-12-22 20:58, hash: rB8d3d4c884084
Worked: (newest version of Blender that worked as expected)

Short description of error
When trying to replace the 'select more'-keybindings for working on a notebook I noticed assigning '+' instead of 'numpad +' the binding then shows as equal-sign '='.
Pressing '+' in any text/search field shows a plus sign as expected, so it is not just a mix up of keys.
Also the keybindings showing the equal sign still work pressing the assigned '+' key, only display inside keybinding editor seems wrong.

Exact steps for others to reproduce the error
Using notebook with german keyboard layout, but english as display language
Open fresh blender 2.91 or 2.92 alpha
Go to preferences > key bindings
search for select more
click one of the key bindings showing 'numpad +' and press ordinary '+' instead (next to 'ä' on german keyboards)
binding will show as '=' instead of '+' as expected.