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Changes between Initial Version and Version 1 of Ticket #24834, comment 5

initial	v1
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11	11	I feel that we want to ensure that people do not needlessly create multiple records, e.g. `example.com`, `example.com:80` and `example.com:443`. This may lead to confusion where other models have a foreign key to `Site` and may lead to "missing" content.
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	13	(Edit: I've just realised that the current implementation would have always supported `domain:port` so as my current version of the PR would break backwards compatibility, although I'm not sure anyone necessarily expected `domain:port` to be work.)