The ECM Page ( https://ntvmr.uni-muenster.de/ecm ) is clearly presenting the primary line text of the ECM where that text is extant; e.g., at Acts 1:10/34-36, it presents  εσθητι λευκη instead of the NA28's ἐσθήσεσιν λευκαῖς .

But the page also presents text for references outside the currently published ECM texts (Mark, Acts, and the Catholic Epistles).

For such other references, e.g. John 1:1; Romans 10:9, etc., which text is being displayed? Is it the NA28 text?

Yes, it is the NA28 text except for Acts and Mark, which displays the ECM text.

Thank you, Greg –

Page 17 (and also page 35) of ECM IV/1 seems to indicate that the Catholic Letters (2^nd Revised Edition – published 2014) were “ECM2/NA28”, the NA28 having been published in 2012.

Would it thus be valid to also refer to the Catholic Letters as displaying the ECM text?  

 

Yes, the ECM page displays the Greek text of ECM Catholic Letters, which is also the text of NA28.