The "1080p Mega" version you're referring to likely pertains to a high-quality video resolution of 1080p, which is a full HD resolution with 1920x1080 pixels. This provides a clear and detailed viewing experience.
Consequently, fans turn to links. Why Mega? Dragon Ball Z Kai 1080p Mega
(now under Crunchyroll/Sony), which cover both the original 98 episodes and "The Final Chapters". Digital/Fan Archiving: The "1080p Mega" version you're referring to likely