Short name: “patch”.

• If $(patch_tex) and $(patch_tex_copy) are different, and

• $(patch_error) doesn't exist,

then

• (re)generate the patch $(patch_file) from $(patch_tex) and $(patch_tex_orig), and

• copy $(patch_tex) to $(patch_tex_copy).

After the patch file is created or updated, consodoc thinks that LaTeX code and PDF are out of date. It's a bit annoying, but reasonable behaviour.