Using buffers https://makecode.calliope.cc/types/buffer/using-buffers
Memory used as temporary location for data in a program is commonly called a buffer. It’s a transfer stop for data coming from some source like a network or pins operation. A program can read the data from the buffer when it’s ready to work with it. Also, programs put their data in a buffer to make it ready for a transfer to a device or to somewhere else in memory on the Calliope mini.
An example of where you might do this is if you have a external display module or