I am the author of fwildclusterboot.
Due to issues with a broken dependency I did not manage to fix on time, fwildclusterboot is temporarily not available on CRAN. The long story is that a dependencies' dependency failed a test, then the dependency was not fixed, therefore archived on CRAN, and I did not manage to a) drop the dependency on time and pass all CRAN notes within the given two-three week time limit. Now I am trying to bring the package back, but CRAN is not very responsive towards me.
In the meantime, you can download the package from R universe (a CRAN alternative, set up by rOpensci) by running install.packages('fwildclusterboot', repos ='https://s3alfisc.r-universe.dev')
. I hope the package will be back on CRAN soon!