A package may be declared absent, and an uninstalled front end is retired for good (hq ADR 0175)

absent: true on a package has the host remove it through the machine's own
package manager when it is installed and leave alone a machine that never had
it; read back either way. Undeclaring a package still removes nothing. A
found firewall whose command is gone is recorded as removed, said once, and
asked nothing of.

internal/system/alpine.go

@@ -46,6 +46,11 @@ func (a alpine) PackageInstalled(ctx context.Context, run Runner, name string) (
 	return strings.TrimSpace(out) != "", nil
 }
 
+func (alpine) RemovePackage(ctx context.Context, run Runner, name string) error {
+	_, err := run(ctx, "apk", "del", name)
+	return err
+}
+
 func (alpine) InstallPackage(ctx context.Context, run Runner, name string) error {
 	_, err := run(ctx, "apk", "add", "--no-cache", name)
 	return err