Types & Levels of testing classification. Where's the source of truth?

Having another discussion around different classification approaches for types and levels of testing recently, I've decided to outline my understanding of the subject here.

Currently the most popular and world-wide recognized professional certification system for QAs is based on ISTQB, having starting point at Foundation Level. So let’s jump from here.

Further.
Last year the version 2018 of ISTQB Foundation Level (hereinafter “the Syllabus 2018”) has been introduced and put into action.

Going on..
ISTQB 2018 uses characteristics of software quality from ISO/IEC 25010 standard (source: page 40 of the Syllabus 2018)
And deeper, with respect to ISO 25010 the classification of software product quality characteristics and, consequently, testing types refers to this:

Product quality model defined by 8 quality characteristics with respect to ISO/IEC 25010

Source is ISO/IEC 25010 standard.

 

Here let me step out and clarify one thing: ISTQB declared correspondence to ISO-25010 standard only in 2018, putting in action new version of syllabus. Interesting here is that by itself 
ISO-25010 has replaced its predecessor (ISO-9126 standard), it actually means that for some 7 years (2011-2018) ISTQB have being stayed based on an outdated quality model. Not a big deal (or it is..), just you'd better know about it now.

 

Coming back to ISTQB, you can find types of testing on page 39+ of the Syllabus 2018.

In their turn, levels of testing are outlined on page 30+ of the Syllabus 2018.

Another frequently discussed point is deeper classification of integration testing level.
Sub-levels (being more specific: strategies) of Integration testing are outlined in “Specific approaches and responsibilities” on p. 34 the Syllabus 2018.

That's easy.

Definitely, there are alternative approaches. One of my favorite is spotlighted in SWEBOK v.3.0.
Though - again - so far only ISTQB is the only well recognized certification for testers all over the world and I believe trustworthy enough to be the single source of truth.