

https://source.android.com/docs/setup/contribute/licenses says most of the Android userspace is Apache 2 licensed. While they can’t close source the Android branch of the kernel, they could close-source new userspace code and it would probably diverge from the last open source release quite quickly.
Realistically, that would probably be sufficent to make Android functionally closed-source, even if the GPL bits were still available.
#\s+
is:#
: a literal#
\s
: any whitespace character (space, tab etc)+
: the previous thing (here the whitespace), one or more timesIn words: “a hash followed by at least one whitespace character”
#[^\s].
is:#
: a literal#
[^\s]
: a negated character class. This matches anything other than the set of characters after the^
.\s
has the same meaning as before, any whitespace character.
: matches any single characterIn words: “a hash followed by any character other than a whitespace character, then any character”.
https://regex101.com/ is really good for explaining regex