iReal Pro has its own internal code for the chords, barlines, spacing etc. so it is not easily possible to extract the chords as text even though the resulting PDF might look simple.
We provide musicXML export so this could go into Logic (also Sibelius etc.) so you might be able to get chords as text from Logic (I have not looked into this) or use the xml file and script a 'find/change' (or if you know, regex) so you are left with the text of the chords.

What are you wanting to do if they could be extracted? Is it for ChordPro format?