- icons must be in a frame 512x512 px
- plain svg
- only one path (remove groups, multipath etc...)
- Remove all fills and colors.
- Remove all FAT line attributes.
- Join all contours to a single outline.
- Select all
- Document Properties -> Resize page to drawing or selection
- Object -> Ungroup
- (Path -> Stroke to Path – use only if necessary, fixes various issues but makes file a lot larger)
- Path -> Union
- Path -> Combine
- File -> Clean up document (or Vacuum Defs)
- Set the document to use PX units
- Save as -> Plain SVG
- icomoon.io