If you have a config.xml w/o a BOM in UTF-8 and try to use cordova build on BlackBerry, you'll get an error.
cordova cli on the other hand seems to only handle UTF-8 (and not UCS2/UTF-16).
That logic is here:
The specification for config.xml is here:
Let doc be the result of loading the widget config doc as a [DOMCore] Document using an [XML] parser that is both [XMLNS]-aware and xml:lang aware.
[XML] defers to:
The mechanism for encoding character code points into bit patterns may vary from entity to entity. All XML processors must accept the UTF-8 and UTF-16 encodings of Unicode [Unicode].