https://www.pcgamer.com/a-new-destiny-2-bug-buffs-equipped-weapons-by-25-percent/

Destiny 2 2.0 rolled out earlier this week, and for those with the One Thousand Voices exotic fusion rifle, the game just became 25 percent easier. As Destiny 2 streamer xgladd discovered, equipping that fusion rifle buffs all equipped weapons by 25 percent – both in primary and secondary slots, but thankfully only in PvE settings.

Here's xgladd demonstrating the buff: