I have a flycheck-clj-kondo question posted in #clj-kondo

but I’m not seeing the flycheck-clj-kondo listed in melpa packages

I think you shouldn't be using the package-install in spacemacs. For clj-kondo, I've set this up in the .spacemacs file: • SPC f e d • in dotspacemacs-configuration-layers

(clojure :variables
              clojure-backend 'cider
              clojure-toplevel-inside-comment-form t
              clojure-enable-clj-refactor t
              clojure-enable-linters 'clj-kondo)

you might also need the syntax-checking layer, but I can't remember

@ps If you have LSP enabled for Clojure, then you do not need to add clj-kondo, lsp will already provide that. If not using LSP, then yes as Shan says, add clj-kondo to the clojure layer using clojure-enable-linters 'clj-kondo, You will need the clj-kondo binary installed on the operating system executable path which is recognised by Emacs, check with SPC f e e and see the value of PATH Spacemacs develop branch is required As is the syntax-checking layer

Any packages installed with package-install will be removed by Spacemacs the next time Emacs is restarted. There are a great many layers available with Spacemacs, removing the need to install packages directly https://develop.spacemacs.org/layers/LAYERS.html