Questions about the manipulation of the jump list. The jump list remembers the previous jumps and allows the user to navigate in the buffer to the location of the previous modifications.

From :h jumplist:

Jumps are remembered in a jump list. With the CTRL-O and CTRL-I command you can go to cursor positions before older jumps, and back again. Thus you can move up and down the list. There is a separate jump list for each window. The maximum number of entries is fixed at 100. {not available without the +jumplist feature}

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