Not handling old file correctly - AdvAgg

Problem/Motivation

Found another old file not being handled correctly from the advanced aggregates module.
On modern (8.1+) PHP getting this error:

Deprecated function: preg_split(): Passing null to parameter #2 ($subject) of type string is deprecated in Drupal\api\Formatter::processPattern() (line 1292 of modules/contrib/api/src/Formatter.php).

Drupal\api\Formatter::processPattern('!'([a-zA-Z0-9_\x7f-\xff]+)'!', NULL, '\Drupal\api\Formatter::linkName', Array, '\Drupal\api\Formatter::makeDocumentationLinks', Array, , '', '') (Line: 1138)
Drupal\api\Formatter::makeDocumentationLinks(NULL, Object, '2724', NULL, Array) (Line: 2894)
Drupal\api\Formatter::linkCode(NULL, Object, '2724', NULL, '1') (Line: 2637)
Drupal\api\Formatter::preparePageFileVariables(Object) (Line: 419)
Drupal\api\Controller\OutputController->branchExplicitRoute(Object, 'advagg_css_compress!csstidy!class.csstidy.inc', Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 580)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 163)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 74)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 692)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

But I don't think that is the real error.
Ex: https://nickdickinsonwilde.ca/en/work/drupal-api/advagg/advagg_css_compr... doesn't show any content under source
https://nickdickinsonwilde.ca/en/work/drupal-api/advagg/advagg_css_compr... does have full source.

PHP file: https://git.drupalcode.org/project/advagg/-/blob/7.x-1.x/advagg_css_comp...

Steps to reproduce

Add AdvAgg 7.x-1.x to site and navigate to that path.

Proposed resolution

Fix tokenization? Not sure that's what is going wrong but my first guess.
If you want to say, old not fixing it won't complain. (Right now i'm a bit busy and probably won't be investigating it properly)