Another term for a grant of citizenship is naturalization. The date the grant is approved or a person takes the oath of citizenship, depending on how the grant works, is the effective date of their citizenship.
I'm assuming what you mean is what was in my specific submission, which was on the questions of subsection 5(2) and paragraph 3(1)(e).
With subsection 5(2), when the grant was approved, IRCC would send out a letter saying, yes, we agree that your parent was Canadian. They were the wrong gender and therefore, we are going to approve you with a grant. Your effective date of citizenship is the date of this letter.
For somebody whose citizenship was restored afterwards, with restoration they took everyone back. They created a bit of a magic pencil and said they would go all the way back in time to someone's date of birth and deem them to have been a citizen the entire time.
For those individuals I mentioned with respect to subsection 5(2), that's what happened to them in 2009. In 2009, they retroactively cancelled all those grants. They made them all retroactive to the someone's date of birth. In our submissions, it says their children were never put into the system, so under subsection 3(4) there was a transition clause that, if somebody was a citizen, they would be able to continue to maintain their citizenship if they were born in a second or subsequent generation.
With the subsection 5(2) applicants, there was an exemption. They said, if you had a child born in a second or subsequent generation, you would not have your citizenship restored retroactively.