nezzie The last 2 versions of opera have failed to start with error: opera: symbol lookup error: opera: undefined symbol: av_stream_get_first_dts Renaming /usr/lib/opera/lib_extra/libffmpeg.so to /usr/lib/opera/lib_extra/opera-libffmpeg makes it loadable.
demm Nothing to do with pacman/updating, just an upstream change of what naming it looks for. Bug reports are best for this, but in this case, the symlink to chromium-ffmpeg files during packaging needs to be renamed then (removing the link fixes startup too, so might be opera needs newer codec, but Falkon can't use newer yet): https://github.com/KaOSx/apps/blob/master/opera/PKGBUILD#L32