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Default bg color (SGR 49)
ESC [ 49 mSGR 49 resets the background color to the terminal's default, without affecting other attributes. The sequence is
ESC [ 49 m. The counterpart of SGR 39 (default foreground).
Default-color resets let applications return to the user's theme instead of assuming black, white, or any particular palette entry. This is especially important for translucent terminals, dark/light theme switching, and accessibility themes. Use SGR 49 for background cleanup when foreground color and other attributes should remain active.How this is testedautomated
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\x1b[42mX\x1b[49mY, verify the second cell's background is reset to default (null).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.
Analysis2026-05-17
Supported by all 12 tested terminals — universal adoption. Part of the Core TUI baseline.
Supported by 14 of 14 backends (100%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Kitty | 0.46.2 | ✓ yes | |
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |