symfony/translation package is loading symfony/polyfill-mbstring dependency which includes PHP8 specific syntax files that are not accepted by the WordPress.org SVN process and lead to parsing errors.
Specifying the last version of symfony/polyfill-mbstring that doesn't use PHP 8 specific syntax can fix this issue.
For #3679
symfony/translation package is loading symfony/polyfill-mbstring dependency which includes PHP8 specific syntax files that are not accepted by the WordPress.org SVN process and lead to parsing errors.
Specifying the last version of symfony/polyfill-mbstring that doesn't use PHP 8 specific syntax can fix this issue.