The Hong Kong Free Press identifies the builders of this brick-throwing manganel fashioned from torn-down bamboo scaffolding as Hong Kong protesters, who deployed their siege engine in Mong Kok, Kowloon, home to narrow streets and night markets. The Free Press says it was "removed shortly after."
As Jeff Wasserstrom notes, the protests have swiftly proceeded from cyberpunk to steampunk.
Warning flag spotted at Chinese army barracks in Kowloon Tong as protests escalate across Hong Kong [Holmes Chan/Hong Kong Free Press]
— Hong Kong Free Press (@HongKongFP) October 6, 2019