people with experience who want a refresher on computer science principles and other things that are important to a software developer

CS is a very broad and deep subject so I think cruising a few intro or 2nd/3rd year course websites will help you figure out what interests you. Learn what interests you. The other way to get exposure to new ideas is to watch conference videos.

Keep in mind software engineering books, like many that have been recommended in other comments, won’t cover the same things as computer science books. If you are looking for more theoretical knowledge, many universities publish slide decks, lecture notes, lecture videos (MIT), homework, book lists, etc. I highly recommend reading any research papers they link to; this is more common in upper level courses. Once you dig into a few research papers, you’ll find a ton of things to explore. Just follow the citations, and use Google Scholar and CiteSeer to find related papers.

I lean toward theoretical knowledge and I love finding ways to apply it. I know many other people get by without academic study and that’s okay too. But don’t let them dissuade you from learning theory if you find it interesting. You will find ways to apply the knowledge if you keep an open mind.

Lastly, becoming a senior engineer requires more than technical skill; soft skills are very important. Look at the jobs you want to have and figure out what specific things you want to improve. You might not need to rehash things you learned in school.

For a quick pick, I recommend picking up “Understanding Computation” https://learning.oreilly.com/library/view/understanding-computation/9781449330071/.