Specify injection point
Specify injection point

Greasemonkey injects to content-script context by default, but
Violentmonkey injects to page context by default. This directive
specifies that the script should run in content-script context.

See also:
 - https://violentmonkey.github.io/2018/11/23/inject-into-context/
franklinyu/snippets,franklinyu/snippets,franklinyu/snippets