The tiarmclang compiler RTS supplies three different variants of the printf family of functions: minimal, no float, and full.  These variants trade-off memory required (both code size and stack) for features supported.  The compiler chooses among these variants automatically.  It keeps track of the format specifiers used (%s, %d, etc.), and chooses the smallest variant that supports those format specifiers.  

Consider the use case of a someone who, as part of a larger effort to reduce memory use, wants to be sure the minimal variant gets used.  What specifiers are available, or must be avoided?  The documentation does not say.  Please add this detail to the documentation.