About Is developed from Open Sans. Main changes include:
Bulgarian alternates for Cyrillic;
True tabular figures (0-9, currencies, and punctuation);
Flattened alternates for single-storey ?g?, serifed ?I?, and non-descending ?J?.
It also has a sister serif family, Avrile Serif.
The Noto and Open Sans fonts present in 1001Fonts are severely outdated, so we forked that family and are posting it here.