I would like to get the open curly brackets ⦃ and ⦄ with pdlatex and latex (not with {xe|lua}latex). Is it possible to get these symbols without loading stix (or, at least, without loading all of stix, though using a font slot for only two chars might be a waste if you have too many fonts already)?
should produce ⦃ s ↦ t ̂u ⦄ (with the wide hat instead of the narrow one). By default, I load a bunch of other packages, including newtx, mathtools, amssymb and stmaryrd, but the open braces seem not to be there. Of course, one can tikz them in different sizes and then apply \mathpalette or even metafont them, but that would be the last resort.