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CSI u Key Encoding
The fixterms/CSI u encoding reports keypresses as CSI codepoint ; modifiers u sequences. This was the precursor to the Kitty keyboard protocol and provides unambiguous key identification for terminal applications.
How this is tested: Check if terminal supports CSI u encoding by querying keyboard mode.
Supported by 4 of 12 backends (33%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ? unknown | |
| Ghostty | 1.3.1 | ? unknown | |
| cmux | 0.62.2 | ? unknown | |
| Kitty | 0.46.2 | ? unknown | |
| VS Code | 1.112.0 | ? unknown | |
| Warp | 0.2026.03.18.08.24.03 | ? unknown | |
| Cursor | 2.6.21 | ? unknown | |
| Terminal.app | 2.15 | ? unknown |