Access your Firefox Bookmarks in Roundcube
With this plugin you can access your Firefox Bookmarks inside Roundcube. I don't know if other browser have similar functionality, since this is only tested with Firefox where it works at least from Version 3 to the current 58.0.x .
This plugin cant sync bookmarks and is only meant for have read access to Mozilla Firefox Bookmarks.
Update As i have learned today, you can export also Bookmarks in Internet Explorer and this Chrome Browser as html file. In both browsers, the exported bookmark file seems to be compatible with this plugin. However, since I didn't use Internet Explorer or Chrome, I can't tell you if there is a way to export these bookmarks automatically. Maybe there are scripts, add-ons or advanced settings. The only reasonably comfortable way I found is in Firefox. This is described in detail in the FAQ.