Monospaced typography, dark themes, syntax-highlighted code blocks, grid overlays, ASCII art, terminal-inspired UI patterns, data visualisation elements, and exposed metrics or version numbers all contribute. The style suggests that the viewer is getting a look behind the curtain.
Developer tools, API platforms, infrastructure products, and engineering-focused companies adopt this style to signal credibility with technical audiences. It communicates "built by developers, for developers" and creates immediate rapport with viewers who value substance over polish.