This extension will open PDF documents in a browser tab. It uses K-Meleon's javascript engine instead of NPAPI so you get the security benefit of K-Meleon's security patches and bugfixes. JustOff built this years back for Pale Moon but it's no longer available from the Pale Moon Add-Ons site or GitHub. This unofficial build has been modified slightly to work on K-Meleon, but most of the work comes from JustOff. It's open-source software and the icon uses artwork from Lim Chee Aun's Phoenity Aura, which is also K-Meleon's default theme.