It's not uncommon to see discovery requests and 30(b)(6) topics asking about the location of documents. In fact, up until 2015, Rule 26 specifically provided for this kind of discovery:
Parties may obtain discovery regarding any nonprivileged matter that is relevant to any party's claim or defense--including the existence, description, nature, custody, condition, and location of any documents or other tangible things . . . .
FRCP 26 (2014).
In 2015, in a (highly commendable) effort to shorten Rule 26, that example was dropped. Now it just reads:
Parties may obtain discovery regarding any nonprivileged matter that is relevant to any party's claim or defense and proportional to the needs of the case . . …
