This book is available as a PDF, always synchronized with the latest changes, at https://github.com/j-jorge/counting-in-cpp/releases/download/continuous/counting-in-c++-wip.pdf.
It is also provided as a website at https://julien.jorge.st/counting-in-cpp/, in good old HTML format.
Finally, the LaTeX source files are stored in a Git repository at https://github.com/j-jorge/counting-in-cpp.