This task is going to adding a unified panel for editing attributes of the selected element by value in edit mode. It makes users able to pass arbitrary per-element data to geometry nodes, opening up more possibilities for procedural modeling.

All data types (int, color etc.) should be supported.
Domain supports should match selection modes in edit mode (eg. no face corner support for meshes).

Basic

Attributes on the active element is listed in the side panel.
Items are grouped by domain.

Multiple Selection

for float types (float, vector, 2d vector):

• Show a mean value computed from all selected elements.
• Button offsets values of all selected elements.

for other types:

• If an active element with a matching domain exists, show the value of it.
• Button only affects the value of the active element.

Fill operators are provided for batch editing. It fills current button value into all selected elements.