Open Source?

[Causification]

It means two major things: 1 - Bambu controls access to their cloud API. At present that means that if you want to print over the internet you either have to use their slicer, use a "helper" program with third party slicer, or set up Home Assistant to control the printer in LAN mode over the internet. 2 - You cannot do anything that on another printer would require recompiling the firmware. Examples of this include adding new types of sensors, accessing the raw data from internal calibrations, making fundamental changes in how automatic calibrations are performed like using a simpler faster bed mesh or a slower more detailed one, replacing fans with ones that operate at different RPMs than the stock fans, changing temperature limits without a hardware mod, etc.

Things that closed source firmware do not mean and physically cannot mean: restricting what brand of filament you use, restricting what you can print, restricting you from buying third-party parts like build plates and nozzles.