What is in an MGF file?

Even if I'm the only person to ever reference this, I'm going to make a short series of this -- just to keep them straight.
We'll start with an easy one:  What information is contained in a Mascot Generic Format file (MGF) file?

Via Proteome Discoverer 1.3, I exported some Orbitrap Velos RAW data into every possible format.  The MGF file looks like this when opened in a spreadsheet

So, you get whether the mass is monoisotopic, or averaged, in this case - mono.
"BEGIN IONS" denotes that this is the place where Mascot should start paying attention, the Title line is a short statement that identifies this spectra.
 The first information is the parent ion mass. The next number is the parent peak area.  This is optional information that is not used in Mascot
The next line provides the charge state.  In our data, this was assigned within the Orbitrap when the isotopes were successfully resolved.
The retention time and the scan number are next, followed by the fragment ions and the area of their peaks (again, this is optional).  The last line is to tell Mascot to stop paying attention and to start looking for the next "Begin Ions" statement.

Did you notice what was missing?  Charge state assignment for the fragment ions.  In high resolution mass spectrometry, it is possible to resolve the charge states for most of the MS2 fragments.  In this experiment, the fragment ions were read at high resolution, and the majority of fragments were isotopically resolved.  Mascot DOES NOT use this information.  As high resolution mass spectrometry continues to advance and MS2 charge state assignments become the norm, the Mascot algorithm will eventually need to be updated or replaced by algorithms that do use this extremely important information.  At this point, however, the Orbitrap is producing more valuable information than we actually know how to use.