Use Unicode abbreviation μs for microseconds instead of ASCII us which made me wonder for a while what that is.

mb_chr is available since PHP 7.2.0 (which Phorge requires). Entering μ directly makes lint bark about "Bad Charset".

Go to http://phorge.localhost/herald/transcript/1/profile/ and look at values in the "Cost" column.
Works with PHP 8.3; no clue which prehistoric PHP versions may have problems.