Установил kcachegrind.
Запустил /usr/bin/pprof2calltree без аргументов.
Получил run-time ошибку:

$ pprof2calltree 2>&1 | tee pprof2calltree.err

[ ... ]

# This script is designed to convert the pprof output from 
# APD (https://pecl.php.net/apd/) to one readable by kcachegrind. To use
# this script:
#
# 1) Install APD.
# 2) Profile your script with APD accordingto the directions in it's
#    README file.
# 3) Take the pprof trace file for your script (pprof.XXXXX.Y) and run it 
#    through this script as follows:
#    > pprof2calltree -f pprof.12345.1 
#    This creates a new file cachegrind.out.12345.1
# 4) View your trace with pprof2calltree cachegrind.out.12345.1

PHP Warning:  require(Console/Getopt.php): Failed to open stream: No such file or directory in /usr/bin/pprof2calltree on line 51
PHP Fatal error:  Uncaught Error: Failed opening required 'Console/Getopt.php' (include_path='./:/usr/lib64/php/:/usr/lib64/php/8.2.27/:/usr/share/php/pear/:/usr/share/php/modules/:/usr/share/php/8.2.27/modules/') in /usr/bin/pprof2calltree:51
Stack trace:
#0 {main}
  thrown in /usr/bin/pprof2calltree on line 51

Видимо, какой-то компонент, необходимый для работы pprof2calltree, не подтягивается в зависимостях.