What does Ezekiel 41:21 mean?

The main sanctuary had square doorposts. In front of the Most Holy Place, there was something that looked like an altar made of wood. Ezekiel 41:21 - Modern Text Bible

(The architecture is described here: the doorways are square, and there's a wooden structure in front of the innermost room, likely an altar or table, marking the sacredness of the space.)