Jottoochauc37
All cable cars, railways and buses between Mürren and Lauterbrunnen are considered as public transit for the resident population of Mürren, and are therefore also included for free in the Swiss Travel Pass and other similar travelcards. The purely “touristic” cable cars such as Schilthorn (closed right now anyway) are however not included, but with the STP you are entitled to a discount of 50% in most cases.
Last september, the scanners at the turnstyles in the cable car stations were able to directly scan QR codes of SBB tickets from the SBB Mobile app, therefore any other QR code should work as well. But there’s a staff member standing right next to the turnstyle anyway, who could visually check your ticket and let you pass through in case of problems. So no ticket exchange is required there.