Hello Dino, if possible you might want to install the package php7.3-intl-dbgsym matching to your php7.3-intl. That is in a separate repository [1].
Then that last frame should show up in the debugger with a function name and line of source code. Kind regards, Bernhard [1] https://wiki.debian.org/HowToGetABacktrace#Installing_the_debugging_symbols
