The link syntax is pretty straightforward:
* {{{attachment:the_file.txt}}} creates a link to the attachment {{{the_file.txt}}} of the current object
* {{{attachment:wiki:MyPage:the_file.txt}}} creates a link to the attachment {{{the_file.txt}}} of the !MyPage wiki page
* {{{attachment🎫753:the_file.txt}}} creates a link to the attachment {{{the_file.txt}}} of the ticket 753
