Bug#922817:
Credit where it's due: Thanks to Matthew Waters for finding this!
Bug#922817: neon library variant no longer installed, ARM performance regression
Package: libvpx Version: 1.6.1-3+deb9u1 In Debian Jessie, ARM VP9 decoding was working well on many platforms thanks to the neon library additionaly provided at /usr/lib/arm-linux-gnueabihf/vfp/neon/libvpx.so.1. However, as of Debian Stretch (and also in Debian Buster), the neon library variant i