When does one become a permanent resident from the N-400 standpoint?

Question

Looking at the N-400 Application for Naturalization Form, I read on https://www.uscis.gov/forms/uscis-early-filing-calculator (mirror):

You may file Form N-400, Application for Naturalization, 90 calendar days before you complete your permanent residence requirement if your eligibility for naturalization is based upon being a permanent resident for at least 5 years.

And on Naturalization Requirements Information (mirror):

Demonstrate continuous permanent residence in the United States for at least 5 years. (In some cases, this may be 3 years if you are married to a U.S. citizen.)

Assume a French citizen living in the United States applies for EB2-NIW, then I-485, then gets an EAD card, and eventually gets a green card, with the intent of filing the N-400 form as the next step after a few years living in the US.

When does one become a permanent resident from the N-400 standpoint?

Answer 1

If one got permanent residency by applying for Adjustment of Status (I-485) from within the US, they usually became a permanent resident when the I-485 was approved.

If one got permanent residency by doing Consular Processing at a US consulate abroad for an immigrant visa, they became a permanent resident the moment they entered the US with that immigrant visa.

The date one became a permanent resident is listed on one's green card, as the "Resident Since" date.