It was posited to explain the occurrence of nouns and verbs in Slavic languages which are invariantly accented on the inflectional ending.
This caused the phonemicization of the previously automatic quality variations between short and long vowels — e.g. short *o vs. originally long *a. Word-final syllables with the Balto-Slavic acute register were shortened and then lost the acute, before the time Dybo's law operated.
It is described as a series of rightward accentual shifts in various Late Proto-Slavic dialects, with successive removal of accent drift prohibitions.
In part, this can be traced to the historically attested self-names of speakers of this type of dialects: Slovenes, Slovaks, Slovincians, Novgorod Ilmen Slavs.
Like Dybo's law, it caused a rightward shift of the accent from non-acuted syllables and a split in the original accentual paradigms.