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Version query (OSC 702)
ESC ] 702 BELOSC 702 returns the terminal's version string. The sequence is
ESC ] 702 BEL and the terminal responds with its name and version (e.g., rxvt-unicode 9.30). This is a rxvt-unicode-only extension, predating modern terminal version-detection mechanisms like XTVERSION (CSI > q) and DA1/DA2/DA3 fingerprinting. Modern applications use XTVERSION instead, which is supported across xterm, foot, Kitty, Ghostty, WezTerm, and many others. OSC 702 is essentially urxvt archaeology.How this is testedpartial
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OSC 702 BEL and verify the terminal responds with a version string or silently consumes the query.The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.
Analysis2026-04-06
Supported by all 4 tested terminals — universal adoption. Part of the Unicode baseline.
Supported by 6 of 14 backends (43%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| Terminal.app | 2.15 | ✓ yes | |
| Kitty | 0.46.2 | ✓ yes | |
| VS Code | 1.113.0 | ? unknown | |
| Warp | 0.2026.03.18.08.24.03 | ? unknown | |
| Cursor | 2.6.21 | ? unknown |