{"name":"COLORFGBG","slug":"colorfgbg","family":"env","title":"Environment variables","noun":"environment variable","description":"Fallback for telling whether the terminal background is dark or light when no system theme has been cached: the last `;`-separated field is read as a color index, where `0` to `6` and `8` mean `dark` and `7` or `9` to `15` mean `light`. A missing, empty or out-of-range value gives no answer, and one caller then uses `dark`.","description_source":"code","described_by":{"bundle":"2.1.286","author":"claude-opus-5-5"},"presence":{"first_seen":"2.1.138","removed_in":null,"in_current_build":true,"newest_mined":"2.1.309","builds":150,"mined_builds":150,"first_cited":null},"aliases":[],"entries":[{"version":"2.1.84","anchor":"theme-detection-auto-match-terminal-replaces-auto-follow-sys","heading":"Theme Detection: \"Auto (match terminal)\" Replaces \"Auto (follow system)\"","line":null,"released_at":"2026-03-25 23:50:13","reason":"found in this entry's text"}],"entries_total":1,"docs":[],"docs_total":0,"gates":[],"related":[],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/colorfgbg","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}