adafruit/Thermal-Printer-Library — comment on commit 55a6db28518398ae06cfd78f2d4b2377e0c685e9
File: Thermal.cpp line 191
By lazyatom:

According to the datasheet (p14), `27,32,n` is "Set and cancle [sic] bold font", but that's immediately below another definition for setting bold using `27,69,n`. So yeah - fun.