What means
The lower two rows are filled; the top is empty.
A sextant is one screen character cell split into six small cells, two across and three down. Here, cells 3, 4, 5 and 6 are filled.
Why are the Teletext cells separated?
The background gaps keep each picture cell distinct.
A 1974 Broadcast Teletext specification describes six-cell mosaic graphics and a separated mode with background-colour gaps around and between the cells.
A 2021 Unicode proposal sought standalone characters for these patterns, supporting Teletext emulation and older files that used a private-use area: code positions set aside for particular systems.
Don't confuse it with
4Questions people ask
1Why does show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type
𜺌\1CE8CCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.