<https://forums.getpaint.net/topic/17805-tool-plugins/#comment-306156>
<http://schema.org/text>
"Tool plugins aren't currently possible. \nA big theme for PDN 4, however, is extensibility. Not promising tool plugins necessarily -- it's still a long ways out. "
<https://forums.getpaint.net/topic/17805-tool-plugins/?tab=comments#comment-306400>