Impulse Tracker Project.
ITP was a module format like IT but with the samples not included in the same file? or I'm wrong?
Yes, you're right.
To be precise, instruments were not included in the file. Samples not associated with any instrument (which in sample mode is of course every sample) were still embedded in files. The format was very inflexible for this and other reasons, which is why it's no longer used. MPTM with external samples is much more flexible.