The OoT section of ZSR lists Door of Time Skip, Forest Escape, early Well/Spirit/Shadow and Trials skip as Sequence breaks. I think its obvious that those would be off limits.
What else counts as a sequence break? Heres a list of a few i'm curious about:
- Skipping the water temple cutscene (filling the lake)
- Skipping Child portion of Spirit Temple
- Water Temple without doing Ice Cavern
- Jabu without getting ruto's letter
- Mido Skip
- Skipping Saria's song (intended to be used to gain entrance to dodongo and forest temple)
- Skipping Red/Blue tunic
- Skipping epona
- Stealing Epona with hover
I think a true "no sequence break" would have you completing all of the objectives the game designers intended, in the order they intended. Whereas glitchless allows you to use developer oversights to any end, this run would force us to figure out what the developers intended us to do at each step. The problem being, the developers never intended for us to do most of the things we do, and anything that deviates from a "casual" route could be considered a sequence break at some level. Eg, Wrong Warping from Fire Temple to Forest Temple, while not technically out of order (IIRC you can do the first 3 medallions in any order, though the NPCs tell you to do Forest->Fire->Water) it could be argued that skipping the walk (including playing saria's song and the minuet cutscene) is a sequence break because you skipped story elements along the way.
If this category is truly to be made, some non-arbitrary definition of a sequence break has to be determined, or some group of people need to go through every sequence break in the game and determine which are okay and which aren't. The problem with the latter is at that point the route will be 100% set in stone, which doesnt make for a very interesting category.