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

[Era Scarecrow via Digitalmars-d]

On Tuesday, 26 January 2016 at 13:16:10 UTC, Wyatt wrote:
> On Tuesday, 26 January 2016 at 12:42:37 UTC, w0rp wrote:
>> Do we want @ for every attribute or not?
>>
> Yes.

  I'll agree. A number of the attributes that use @ won't be an 
option to use without the @; And having a half & half (or more 
like 1/3) better consistency and not having to remember special 
rules for which attributes use @ (and which don't) is one less 
thing I'd have to worry about.

  Although the @ could just be reserved for UDA's but that seems 
unlikely...