Hi Tim, > It would probably be good to add the two above packages as part of the > ’default’ package preamble, but this would require considerable testing > as it isn’t known if there will be adverse effects when mixed with other > packages. Those packages are early accessibility experiments, and are /not/ intended for wider use. See the top of the README: “Prototype. Not suitable for production”. The author themselves said in a [2020 tex.SE answer] that: `accessibility' was developed and published back in 2007 as a proof of concept for some of the KOMA document styles. I got hold of the files from the author in 2019 and took over maintenance with her permission. I tidied up the package enough to get it to CTAN, but didn’t update the functionality. I also published it to GitHub to get some feedback on it. It seems to have worked well in 2007 for a few test cases. Unfortunately it now fails every test case, and it looks like needing some serious efforts to fix. Because of this I no longer think that accessibility is fit for purpose. They also go on to make a comment I’ve seen a few times from the people working on the latex3 accessibility project — basically that in order to actually get a /good/ solution, we’ll need to wait till support is baked into the LaTeX core. If we’re desperate to add this, we’ll likely want to look at `tagpdf' which is written by someone working on the latex3 accessibility project. It is apparently capable of passing PCA3, however according to the author: `tagpdf' hasn’t been written as a user package but to allow experiments and tests and to help to identify missing interfaces in the kernel and in packages. It can change at any time in incompatible ways and it requires some skills to use it. So, while it may be a particularly boring answer, I think “wait and see” is our current best bet. All the best, Timothy [2020 tex.SE answer]