Am I right understand the dub.json system?

[Suliman via Digitalmars-d-learn]

For example I have got app that depended on DDBC. In 
configuration section DDBC related on:

"libs-posix": [
"sqlite3",
"pq"
]

Does it's mean that it will try to find this 2 libs in any case? 
Even I do not use them.

If I do not need them what I should to do? Fix 
~/.dub/packages/ddbc and remove this strings from it, or what?