I'm a tenured professional orchestra musician. I'll try to explain.
NotBornYesterday's conclusion was dead on! The AC is also correct.
In the example
, the ancient flute played the pitches Eb, F, G, Bb, and C, which is a simple pentatonic scale. When in this particular order, it's called a major pentatonic scale. It's incidental that the pitches are close to these modern pitches (AC's point). The important thing is the distance from one pitch to the next, or in other words, the ratio of one pitch to another (NBY's point).
The ratios in the pentatonic scale are 1:9/8:5/4:3/2:5/3. So if you set Eb as 1, F is 9/8 of Eb, G is 5/4 of Eb, Bb is 3/2 of Eb, and C is 5/3 of Eb. The ratios are what is important. The absolute value of the pitch in Hertz is incidental. The maker of this flute understood these ratios, and constructed the flute accordingly.
The fact that people were using the pentatonic scale 35,000 years ago or more is stunning.