They were heavily protesting two things. Election rigging by not letting candidates on the ballot (basically China would pick who could be voted for from party approved mainlanders). And an extradition law where hong kong citizens could be taken to the mainland.

The only real development besides constant violent struggle was Hong Kong elections heavily destroyed mainland authority. They basically voted in a majority of pro-secession hong kong politicians. When previously the mainland held a stranglehold on the politics.

Oh and I guess the mainland threatening Taiwan by offering to make them Hong Kong 2.0.

The protest was in response to a “white paper” from Beijing that made clear that only “patriots” would be allowed to run for chief executive in Hong Kong. To many in Hong Kong, this signaled that Beijing intended to keep a tight rein on Hong Kong’s political reforms — and political autonomy.>