Here's what the changelog said for 8.0a1 "Binary data support. The new compiler C APIs allow any Tcl value to contain arbitrary binary data (strings are count

Here's what the changelog said for 8.0a1 "Binary data support. The new compiler C APIs allow any Tcl value to contain arbitrary binary data (strings are counted in addition to being null terminated)." I take that to mean it was probably a struct with a size and a buffer.