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Font ligatures
Font ligatures are font-level glyph substitutions that render specific character sequences as a single combined glyph — for example
!= rendered as ≠, => as ⇒, -> as →, or <= as ≤. Programming-oriented fonts like Fira Code, JetBrains Mono, Iosevka, Cascadia Code, and Monaspace ship with large ligature tables targeting common operators and symbols in popular languages.
Ligature support is a terminal renderer feature, not an escape sequence protocol: the terminal decides whether to honor the calt / liga / dlig OpenType tables when shaping runs of monospaced cells. Terminals that opt in must also handle cursor positioning carefully — the cursor should still land on logical character boundaries even though multiple cells display as one glyph, and selections must split ligatures when partially covered.
Known support: Kitty, WezTerm, Konsole, iTerm2 (opt-in), Alacritty (opt-in, limited), Ghostty, foot, and VTE-based terminals. Not supported by xterm, Terminal.app, or Windows Console Host. Because this is a rendering decision rather than an escape-sequence feature, it cannot be detected via any query protocol — only by visually inspecting output with a ligature-enabled font.How this is testedunprobed
Manual verification required — no automated probe available.
Manual verification required — no automated probe available.
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.
Supported by 0 of 14 backends (0%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ? unknown | |
| Ghostty | 1.3.1 | ? unknown | |
| Terminal.app | 2.15 | ? unknown | |
| Kitty | 0.46.2 | ? unknown | |
| VS Code | 1.113.0 | ? unknown | |
| Warp | 0.2026.03.18.08.24.03 | ? unknown | |
| Cursor | 2.6.21 | ? unknown |