Renamed to ad-si/Vectual. That is where the repository lives now. It has not been published as a package under the new name.
Versions published as adius/vectual still install under that name. 3 versions of 7 come from the new location (see their notes).
Rerouted (renamed, verified). The GitHub user or repository was renamed. The tag is still there, at the new name. The Lamdera package server serves a copy recovered from https://github.com/ad-si/Vectual.
What we checked: The repo moved to github.com/ad-si/Vectual and tag 4.0.0 is there; its commit 0d3f2db59855 is from 2021-02-13 17:06 UTC, before the version was published (2021-02-13 17:07 UTC); elm.json is byte-identical to package.elm-lang.org's; the exposed modules match docs.json; the zip's SHA-1 is not the published one (GitHub's zip no longer comes out byte for byte the same), so the contents were checked instead.
The Lamdera compiler uses this copy and prints a one-line notice saying so. elm itself fails to download this version.
Details · package.elm-lang.org's zip: https://github.com/adius/vectual/zipball/4.0.0/
Return ISO week values year, week, isoDayOfWeek.
Input date is expected to be in local time zone of vm.
Return date of start of ISO week one for given year.
Return year of ISO week date (which can be different than the normal calendar year) and the timestamp of the first ISO week.
Return a list of days dayLength long for successive days starting from startDate.
Now adds 1 day if dayCount is +ve to create day list. Now subtracts 1 day if dayCount is -ve to create day list.
This could be made much faster by using
daysFromCiviland not using underlying date system at all I believe.