The IGNTP is a group of scholars that has met since the mid-1940s. Over 300 scholars worked on collating Greek MSS for the gospel of Luke. In 1984 and 1987, the two volumes were produced that displayed their work: all papyri, uncials, and 168 minuscules were collated, along with all select lectionaries, all fathers up till AD 500, and the major versional witnesses.
The collation was done against the Textus Receptus, not because any of the scholars thought that the TR was the best text, but rather because it was about the worst. Thus, any readings found in the apparatus (against the TR) would have an intrinsic value higher than the TR. But the larger reason for collating against the TR was that they could use the subtractio princeps (principle of listing only variants that disagree with the TR), thereby alleviating the apparatus of much unneeded data that could simply be inferred.
In 1987 the IGNTP turned to John and has now completed the work of the papyri, but the uncials, minuscules, fathers, etc. still need to be completed. No translation is offered, nor are any textual decisions offered in this work. It is primarily for those who wish to know the text-critical data. As you can see, the work of doing solid text-critical work takes decades and hundreds of scholars—even for a small portion of the New Testament.