A new secret police
Article 16 provides for the creation of a Secret Police, nominally with the name (and reputation) of the HKPF, for however long that lasts. The head of the "department for safeguarding national security of the Hong Kong Police Force shall be appointed by the Chief Executive" who is, of course, a puppet of Beijing.
And it is a PRC-manned agency, who may "recruit qualified professionals and technical personnel from outside the Hong Kong Special Administrative Region."
Their duties are "enforcing", plus some other minor duties. They shall "observe the obligation of secrecy."
DSNS, I guess, as an acronym, will become as infamous as NKVD, KGB, and SS.
Long live free HK. Oops, sorry, wrong, it's already done for.