Redux of this question.
Assuming 3.0 is correct, it is correct in section 2 (Network Content).
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The former Section 3 (User Content) is now Section 6 (Content etc.) of the SE Terms of Service page. Section 6 links to version 4.0 by-sa of the Creative Commons license, see last paragraph of that section.
Section 2 (Network Content) is now a separate page, Network Acceptable Use Policy. The footer reads as follows, and includes a link to CC version 4.0 by-sa:
site design / logo © 2019 Stack Exchange Inc; user contributions licensed under cc by-sa 4.0 with attribution required. rev 2019.9.6.34826
The Network Content, User Content, and footers of all "legal" pages now link to the same version of the Creative Commons license, CC by-sa/4.0
Question should be marked status-completed, but only site moderators can, as I was informed when I tried to do so just now.