Why do some attributes start with '@' while others done't?

[Era Scarecrow via Digitalmars-d]

On Thursday, 21 January 2016 at 23:18:16 UTC, tsbockman wrote:
> Adding the @ to the old attributes was discussed as well, but 
> it didn't seem worth the code breakage.

  I have to wonder if it would be that bad, since if you're aware 
of where it breaks (which source code) wouldn't a bulk 
search/replace of the sources to resolve that?

  Although I'll be honest, breaking code is never fun, and making 
people scour their code to fix something that worked before is 
just an annoyance. On the other hand I'm almost tempted to 
suggest a tool that would update changes to source code when some 
of these things happen, dealing with most of these types of 
problems.