FireFox

Отключить кеширование DNS:

Открыть about:config, установить

network.dnsCacheExpiration => 0
network.dnsCacheExpirationGracePeriod => 0

Values in test input fields is not-visible in dark theme

1. Open about:config in Firefox

2. Create a new String value, named widget.content.gtk-theme-override

3. Set a light GTK theme name as the value, for example Arc-Darker

4. Restart Firefox

Work on version: 62.0 (64-bit) Source: https://www.mkammerer.de/blog/gtk-dark-theme-and-firefox/

Firefox, Thunderbird start too slow on Manjaro XFCE

Solution

sudo pacman -Rdd xdg-desktop-portal-gnome
sudo pacman -S xdg-desktop-portal-gtk

Source: https://forum.manjaro.org/t/slow-run-firefox/142268/4