12  Debug package builds

12.1 Is it possible to customize the package build process with custom options/tools/variables?

No, that is not possible. Think of R-universe more like your own mini-CRAN. The build environment is actually very similar to that of CRAN, if the package can build on CRAN, it will probably work on R-universe.

This is on purpose: we want to make sure that the packages deployed on R-universe are reproducible and will work on the user machine as well, and do not depend on some hidden settings or tools.

12.2 How to publish vignettes/articles which require custom software/tokens to render?

The best solution is to precompute these vignettes on your local machine, see: How to precompute package vignettes or pkgdown articles.

12.3 Are packages on R-universe required to pass CMD check or meet other criteria?

No.  R-universe is an open publishing system. The system just builds and deploys R packages from git into personal cran-like repositories. The owner of the universe is responsible for their own policies and quality control.