VSOB 20; ECO_FULL

In last week's engine post, TCEC 'VSOB'; CCC 'ECO Mega-Matches' (April 2021), I gave myself an action:-

[VSOB] sounds like a good topic for an off-week post. [...] I'll look at available info for the ECO Mega-Matches when I look at VSOB. This follows the principle that opposites attract.

Last year I wrote an entire post on VSOB in VSOB PGN (January 2020; 'VSOB stands for "Viewer Submitted Openings Bonus"'). The most recent VSOB event is in the TCEC Archive at S21 - Viewer Submitted Openings Bonus 20 (tcec-chess.com/archive; PGN available from top menu bar under 'Download'). I downloaded the 76 games, loaded them into SCID, and produced the table of first moves shown in the top of the following image.

As for 'ECO Mega-Matches', the PGN is at Eco_full (mediafire.com; 'File size: 248 KB; Uploaded: 2021-04-22'). I downloaded the file, but hesitated when I saw that each PGN game had incomplete headers. Here's the first entry in the file:-

[ECO "A00"]
[Opening "Polish (Sokolsky) opening"]
1. b4 *

That caused no problem for SCID, which produced the table shown in the bottom of the image. The analysis shows that the ECO_FULL.PGN file contains 2014 ECO variations. More than half of the variations start 1.e4.

I wanted to take the analysis further, but ran out of time for this post. Will I find the time to continue? My experience on follow-ups says, 'No!'.