JOSM element icon

[severin.menard via josm-dev]

Hi,

I would like to know what this icon means: 
https://leslibresgeographes.org/jirafeau/f.php?h=2eP5LsxL&p=1

Is it a multipolygon with holes inside?
is there somewhere in the JOSM wiki the varisou icons are liste?

Sincerely,

Severin