I didn't mention it but the Kansas ("Wyandotte" Constitution of 1859) Constitution had this provision as to qualified electors, in addition to U.S. citizens: "Persons of foreign birth who shall have declared their intention to become citizens, conformably to the laws of the United States on the subject of naturalization."
I wonder how many States had similar provisions in the mid-19th Century?
[The voter] shall be a citizen of the United States, or not being a citizen of the United States, he shall have declared his intention, according to law, to become such citizen, not less than four months before he offers to vote. Original Colorado Constitution 1876
Non-citizens could vote in some Eastern states in the early years of the country, and in some Western states down until the First World War.
It was called "declarant alien suffrage" because the foreign-born non-citizens had declared their intention to become citizens.
Colorado's original constitution also required that laws be published in Spanish and German for 25 years, but that provision was never enforced.