Put the watchLater.sh and watchLater.txt to .config/qutebrowser/userscripts/
Put these key bindings to .config/qutebrowser/config.py
config.bind("wl", "spawn bash -c 'echo {url} >> ~/.config/qutebrowser/userscripts/watchLater.txt'")
config.bind("wr", "spawn bash -c 'grep -v {url} ~/.config/qutebrowser/userscripts/watchLater.txt >> tmp.txt && mv tmp.txt ~/.config/qutebrowser/userscripts/watchLater.txt'")
config.bind("wp", "spawn bash -c 'mpv $(~/.config/qutebrowser/userscripts/watchLater.sh)'")