11 files declare their use of Reader in Zircon Profile 8

AbstractHandlerTest.php in vendor/symfony/css-selector/Tests/Parser/Handler/AbstractHandlerTest.php

CommentHandler.php in vendor/symfony/css-selector/Parser/Handler/CommentHandler.php

CommentHandlerTest.php in vendor/symfony/css-selector/Tests/Parser/Handler/CommentHandlerTest.php

HandlerInterface.php in vendor/symfony/css-selector/Parser/Handler/HandlerInterface.php

HashHandler.php in vendor/symfony/css-selector/Parser/Handler/HashHandler.php

IdentifierHandler.php in vendor/symfony/css-selector/Parser/Handler/IdentifierHandler.php

NumberHandler.php in vendor/symfony/css-selector/Parser/Handler/NumberHandler.php

ReaderTest.php in vendor/symfony/css-selector/Tests/Parser/ReaderTest.php

StringHandler.php in vendor/symfony/css-selector/Parser/Handler/StringHandler.php

Tokenizer.php in vendor/symfony/css-selector/Parser/Tokenizer/Tokenizer.php

WhitespaceHandler.php in vendor/symfony/css-selector/Parser/Handler/WhitespaceHandler.php