I still don't quite get the purpose of the 'Backport changes' step

[MichaelChirico]

https://github.com/r-lib/pkgdown/blob/676cf1dce39e4dc5aa1bcb671b1e14e992589a0a/vignettes/how-to-update-released-site.Rmd#L46

https://github.com/r-lib/pkgdown/blob/676cf1dce39e4dc5aa1bcb671b1e14e992589a0a/vignettes/how-to-update-released-site.Rmd#L231

A lot of the writing is focused on how to copy files across branches/tags, but I've read and not come away with a solid understanding of why this is being done. Am I missing something?

PS,

Now you should backport innovations from the future that you would like to retroactively apply to your released site.

the phrasing here ("future", "retroactive") sounds strange to me, presumably all of these changes exist, just in different local branches, so I'm puzzled how I should intuit the time-ordering of the operations. I see similar phrasing was dropped from the current release version of this vignette here:

https://github.com/r-lib/pkgdown/commit/5a0a31f89d7c839c04a929844e4b7216196189ca#diff-63997d65f5d4b9582c4800dbdd9109beeab48afd55d5bcb72ffaba5f4aa91e12L41