Using bower install bootstrap creates the .less file

@cloud4bpm It does, whitin your bower_components there is bootstrap.

Within bootstrap you can find the less files and a "dist" directory containing the .css, .js and font files.

Thanks @uxweb but the question is, using bower-installer avoids to navigate within the components folder and create the distribution files as .js, .css. For this reason was my question, that less file may need to be processed by gulp to obtain the final .css file, or maybe I'm wrong on that question?

There is no need, the maintainer of the package gives you the dist files, but if you want to override some styles or compile it yourself, it includes the less or source files.