check­lab – A patch for the la­bel-check­ing code

Patch for the ker­nel la­bel-check­ing code at end doc­u­ment, to pro­duce an ex­plicit mes­sage (al­beit a some­what in­scrutable one) for each la­bel that it thinks has changed (and how it has changed). This is use­ful if you are de­vel­op­ing macros that use la­bels in odd ways.
One of a se­ries of frag­ments de­signed for use by pack­age writ­ers and oth­ers.