$ latex '\makeatletter\show\e@alloc@top'
This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=latex)
restricted \write18 enabled.
entering extended mode
LaTeX2e <2016/03/31> patch level 3
Babel <3.9r> and hyphenation patterns for 83 language(s) loaded.
> \e@alloc@top=\mathchar"7FFF.