System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.43

Blender Version
Broken: version:

• 2.92.0 Alpha, branch: master, commit date: 2020-12-15 16:03, hash: rB990406e1ff93
• 2.91.0
• 2.83.9
• 2.82a

Worked: Never

Short description of error
With a custom keymap the description in the tool shelf of the 3d view misses the description part of the tooltip here and there. So far detected with an armature in edit mode at the roll and bone size tooltips for example. But it may miss with other tools, objects and modes too.

Exact steps for others to reproduce the error

Create an armature. Switch to edit mode. Watch the Bone Size tooltip.
Open the Preferences. Create a custom keymap. Watch the Bone Size tooltip again. It misses now the description part.

Possible related task, unfortunately without an commit connected to it: https://developer.blender.org/T71423

With the Blender keymap:

With the custom keymap: