Sourdough recipe with vinegar
There are several conversations about this on The Fresh Loaf, which you can search.  Issues raised include (a) acetic acid used as a preservative in manufactured bread (lowering the pH), (b) yeast performing best in a neutral to slightly acid environment, suggesting vinegar might be helpful when using instant yeast, (c) vinegar helping the rise in gluten free situations, and (d) the idea of vinegar, not for help in fermentation, but to strengthen the dough, thus creating a better structure for capturing fermentation gasses.  All of these use vinegar in small amounts (1 - 1.5% of flour).  

My concern, in sourdough situations, would be too much acid.  Starter is typically acidic to start with. When feeding, much of the starter is removed and replaced with fresh flour and water.  In part, this keeps acidity in check.  Too much acid inhibits yeast and bacterial activity.

If you bake often, why not try an experiment?  Use the same recipe and baking conditions, except add 1% vinegar to one.  Let us know what happens!