Firefox Tweaks
Performance
// speed up them sites
network.dns.disablePrefetchFromHTTPS = false
network.predictor.enable-prefetch = true
network.http.max-persistent-connections-per-server = 12
Usability
// Restore system print preview
print.tab_modal.enabled = false
Security
// Upgrade sites to HTTPS where available:
dom.security.https_only_mode_https_first = true
Ublock Origin
Settings > Block fonts = true