OK, I'm reasonably proficient in HTML, but had not seen this tag until today. I came across it on a site running the Invision forum software, only because it is not rendered correctly in Firefox 22.214.171.124. IE 6 and Opera do display it correctly. Does anyone have a link to details on syntax, etc?
<if="->member['g_use_pm'] AND ->member['members_disable_pm'] == 0">