try

borg.el

@@ -139,7 +139,8 @@ default value.")
                             (directory-file-name borg-drones-directory)))
              topdir)
         (locate-dominating-file borg-drones-directory "init.el")
-        (and (file-in-directory-p libdir user-emacs-directory)
+        (and (or (file-in-directory-p libdir user-emacs-directory)
+                 (equal (getenv "CI") "true"))
              user-emacs-directory)
         (error "Could not determine `borg-user-emacs-directory'"))
     "Directory beneath which additional per-user Emacs-specific files are placed.
@@ -156,7 +157,8 @@ directory is used.")
             (file-name-as-directory
              (car (process-lines
                    "git" "rev-parse" "--show-toplevel")))))
-        (error "Could not determine `borg-top-level-directory'"))
+        (and (not (equal (getenv "CI") "true"))
+             (error "Could not determine `borg-top-level-directory'")))
     "The top-level of repository containing `borg-user-emacs-directory'.")
   )