Unofficial DMG files are a common delivery method for malware, adware, and miners. Since the file is unsigned by Apple, you must bypass Gatekeeper to install it, essentially lowering your Mac's defenses.

The standard Apple Disk Image file format used for installing software. The Risks of Using Modified DMGs

So it likely means: .

While the file extension tdmg suggests a cold, technical process, the contents are purely creative. It is the vessel for the tools used to cut the next indie film, the next viral vlog, or the next family memory.

: Automatically generates closed captions directly in the timeline.