src/PubSubHubbub/AbstractCallback.php:238:43: RiskyTruthyFalsyComparison: Operand of type null|string contains type string, which can be falsy and truthy. This can cause possibly unexpected behavior. Use strict comparison instead. (see https://psalm.dev/356)

src/PubSubHubbub/AbstractCallback.php:266:15: RiskyTruthyFalsyComparison: Operand of type non-empty-string|null contains type non-empty-string, which can be falsy and truthy. This can cause possibly unexpected behavior. Use strict comparison instead. (see https://psalm.dev/356)

src/PubSubHubbub/AbstractCallback.php:294:15: RiskyTruthyFalsyComparison: Operand of type non-empty-list<string>|scalar contains type scalar, which can be falsy and truthy. This can cause possibly unexpected behavior. Use strict comparison instead. (see https://psalm.dev/356)

src/PubSubHubbub/AbstractCallback.php:298:15: RiskyTruthyFalsyComparison: Operand of type non-empty-list<string>|scalar contains type scalar, which can be falsy and truthy. This can cause possibly unexpected behavior. Use strict comparison instead. (see https://psalm.dev/356)

src/PubSubHubbub/AbstractCallback.php:340:20: PossiblyNullArgument: Argument 1 of strpos cannot be null, possibly null value provided (see https://psalm.dev/078)

src/PubSubHubbub/AbstractCallback.php:349:16: InvalidNullableReturnType: The declared return type 'string' for Laminas\Feed\PubSubHubbub\AbstractCallback::buildCallbackUrlFromOrigPathInfo is not nullable, but 'null|string' contains null (see https://psalm.dev/144)

src/PubSubHubbub/AbstractCallback.php:354:15: RiskyTruthyFalsyComparison: Operand of type null|string contains type string, which can be falsy and truthy. This can cause possibly unexpected behavior. Use strict comparison instead. (see https://psalm.dev/356)

src/PubSubHubbub/AbstractCallback.php:355:13: PossiblyNullOperand: Cannot concatenate with a possibly null null|string (see https://psalm.dev/080)

src/PubSubHubbub/AbstractCallback.php:357:16: NullableReturnStatement: The declared return type 'string' for Laminas\Feed\PubSubHubbub\AbstractCallback::buildCallbackUrlFromOrigPathInfo is not nullable, but the function returns 'non-empty-string|null' (see https://psalm.dev/139)