Not quite library files, but PBP does have the function to include files, so you could have a "library" file for a function, such as setting up an LCD or using a specific sensor, and then use one line of code in the main file to include that file as part of the main code, but it has the same limitation Henrik mentioned, in that you have to name the variables carefully. It really helps developing your own projects as you know what the variables are called, but to offer them as a general use for different project could cause confusion.
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