The package contains commands
— \showlostmarginals, to output lost marginal notes at the left of the page;
— \enlargefreelist, to provide more free space for marginals and floats (see also morefloats); and
— \onsidemarginals, to force all marginal notes onto the same side of the page, thus leaving space for twice as many notes.

The package is part of the sttools bundle.

The author is Sigitas Tolušis.