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Default bg color (SGR 49)

Category: sgr · Baseline: core · Tags: ECMA-48 Standard · Specification ↗

ESC [ 49 m
SGR 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).
How this is testedautomated
Send \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.

Analysis2026-04-06

Supported by all 12 tested terminals — universal adoption. Part of the Core TUI baseline.

Supported by 14 of 14 backends (100%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
VS Code✓ yes
Warp✓ yes
Cursor✓ yes
Terminal.app✓ yes

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0✓ yes
Kitty0.40.0✓ yes
vt100.js0.2.1✓ yes
vterm0.2.0✓ yes
WezTerm0.1.0-fork.5✓ yes
xterm.js5.5.0✓ yes