Thank you for adding the Greek language.
I just want to mention two errors that I've noticed.
(1) On the lowercase letter "蟻" (rho) there is an extended small line at the upper left of the circle. This is not part of the Greek letter "蟻". It makes it look like the English letter "p".

(2) The uppercase letter "螛" (theta) should have the horizontal line in the center of the circle. Currently in has it above the circle making it look like no letter that belongs to the Greek alphabet.

Yes, seems legit. We will collect some more feedback and add corrections in the next update. Thanks!
Great.
I've also noticed something else on another letter. The lowercase "渭" (mu) should have a small line extension on the lower right side of the U-shaped part. If it was done to adhere to the JetBrains Mono design I guess it's OK. But, strictly speaking, it should have a small line there.

This one is fine. This is dependent on letter u. In JetBrains Mono it happen to not have the right vertical stem placed on the baseline.
Yes when I look at my 蟻p in my code(the density of the planet) I was stunned because IT LOOKS EXACTLY THE SAME!
Thanks to @N3tFX for posting the issue, but here it says that it has the 蟻 letter (the last one, added in v1.0.5), and why there are 2 渭's (in the middle, on line1 and line2)

I am a native Greek speaker and I second @N3tFX's recommendations on the letters capital theta (螛), small rho (蟻) and small mi (渭).
@philippnurullin
This one is fine. This is dependent on letter u. In JetBrains Mono it happen to not have the right vertical stem placed on the baseline.
I disagree. The letter u is not related in any way to the greek letter 渭, regardless of the fact that English speakers sometimes use the letter u as a replacement for the letter 渭.
I am a native Greek speaker and I second @N3tFX's recommendations on the letters capital theta (螛), small rho (蟻) and small mi (渭).
@philippnurullin
This one is fine. This is dependent on letter u. In JetBrains Mono it happen to not have the right vertical stem placed on the baseline.
I disagree. The letter u is not related in any way to the greek letter 渭, regardless of the fact that English speakers sometimes use the letter u as a replacement for the letter 渭.
Yes. the letter 渭 in Greek is similar to the letter m in Latin languages, and 谓 (nu) for n, not u and v.
I saw #356 and I am asking for adding the \phi symbol. This is \phi and \varphi in LM Math. PS: \varphi in JB code looks not so good as the curve should be smoother.

@1900011604 That already exists in JBM: 蠁 (U+03C6, GREEK SMALL LETTER PHI) vs 蠒 (U+03D5, GREEK PHI SYMBOL). The former is used in Greek texts, the latter is used in mathematical and technical contexts (italicized). (Of course, in browser, the appearance of these might vary, depending on the fonts you're using). In JBM, U+03C6 is loopy, and U+03D5 is stroked.
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I am a native Greek speaker and I second @N3tFX's recommendations on the letters capital theta (螛), small rho (蟻) and small mi (渭).
@philippnurullin
I disagree. The letter u is not related in any way to the greek letter 渭, regardless of the fact that English speakers sometimes use the letter u as a replacement for the letter 渭.