The methodology is a survey asking businesses if they have job openings. Openings are not a better indicator than hiring but they're a cleaner one to assess labor demand; you can have a job opening regardless of what's going on with the supply side of the labor market, not so for hirings.
What about all those tech jobs that post fake openings - not intended to every fill the position
There's no real way to account for businesses lying to the BLS tbh, but this is a survey based on asking them officially, not scraping job boards or something like that.
Also Information industry openings have ramped up recently with hires also rising and quits starting to perk up. Pretty strong confirmation that tech labor demand has inflected higher lately.
No bears in sight.