The nine bytes at Leftover_MusicEn to 7296 are the leftover filename @Music.en at the end of the menu-music source block (MenuMusicSource). GameStart copies those bytes to FFF6 with the rest of the block. Nothing in the game prints or otherwise uses the string.

TapeHeaderRemnant to 5F6E hold the ten-character tape header name TRAPDOOR (padded with spaces) left by the loader. The bytes sit in otherwise unused memory between the system variables and the display buffers.

The Bad Tempered Thing aside at Messaging_YourreOnYourOwn stores YOUR'RE ON YOUR OWN. That is presumably meant to read YOU'RE ON YOUR OWN. The typo is in the original game, so the bytes are left exactly as they are.

The aside at Messaging_ImUpstairsWaits stores 'IM UPSTAIRS WAITS. That is presumably meant to read I'M UPSTAIRS WAITS. The typo is in the original game, so the bytes are left exactly as they are.

Flag_LearnerBerkMode is the Learner Berk mode flag. The main-menu chooser at MainMenu_ChooseLearnerOrSuper writes 00 for Super Berk (S) or 01 for Learner Berk (L). Readers include AC07, AC55, AC7D, AEB2, AF5E, Update_ThingUpstairs_Entity and Print_StatusMessages.