Project panel
With nothing selected

The Project panel of a new document: unit, decimals, scale, steps, page layout and the view options

When it appears

With nothing selected. It holds the document properties and, at the bottom, the editor view options.

Fields

FieldWhat it does
Namethe project name, the one shown at the top of the toolbar. The first time you save to a file, it takes the file name
Unitthe unit measurements are read in: mm, cm, m, inch, ft, px, pt. Changing it does not change the drawing
Decimalsthe decimal places of measurements
1 unit =how long one drawing unit is, in the unit written next to it
Scale 1 :the scale denominator (50 = 1:50): it changes the paper, not the measurements
Arrow stepthe arrow key step, in the project unit; ten times as much with SHIFT
Rotation stepthe rotation step with SHIFT and with ALT + arrow keys, in degrees; empty means 15
Page layoutfree: pages stay where you put them; rows: in rows, in their order
Pages per rowin rows: how many pages per row; 0 = a single row, 1 = a single column
Page gapin rows: the space between pages; empty means 20 mm
Fast viewfast pan and zoom (editor setting)
Scale page labelspage labels follow the zoom (editor setting)
Show originthe origin cross of the active page (editor setting)
Show object originthe origin of the selected object (editor setting)
Dark themethe dark theme (editor setting)

Document or editor

The rows up to Page gap belong to the document: they go into the history and are saved. The five after the divider line belong to the editor: they are not undone and not saved.