chriseppstein/sass — comment on commit 52c9084c1e1258473d00274fbf210d6c44ae14ad
File: doc-src/SASS_REFERENCE.md line 1475
By nex3:

After talking this over with @chriseppstein offline, we've ended up with an alternative solution: adding a new type of selector, a "placeholder selector". The syntax is "%foo", and it works just like a class selector except rulesets that use it don't get printed. This avoids most of the tricky complications about whether or not `@silent` is global, the ease of making multiple rulesets silent versus just one, etc. The primary downside is lack of obviousness, but I think that's mitigated by the benefits.