This icon is a part of a collection of Plan piętra flat icons produced by Icons8. Icons follow the guidelines of iOS, Windows, and Android and are designed by a single designer, guaranteeing the consistent quality. Both PNG and vector are available.
The image is a square that isn't fully closed. At the top the line is broken like an entrance. Inside the square are some lines that partially section it off. The lines at the bottom look like a capitalized letter T.