There are many doors in the game that only become openable after a certain event. Typically they require a particular time of day, engaging in a sidequest, or both. It is generally much faster to avoid these requirements by clipping out of bounds to touch the loading zone from behind.
Named for its original discoverer, this trick enables you to clip into the backroom of the Curiousity Shop using a Deku recoil. This enables you to get in at any time of any day. Typically this is most useful on Day 3 since the Curiosity Shop man will always be back here and ready to give you the Keaton Mask and the Expressmail to Mama, even if you did not engage in the Kafei and Anju sidequest this cycle.
A modern, fast setup for this trick is shown below. If you prefer, it's also possible to use c-up to line up if you pull bomb later.
Typically entering the goron shrine requires talking to the goron and watching a lengthy cutscene of the door opening (or goron pounding in front of the door). Clipping through can be slightly faster.