Guillemet

[6] In Adobe software, its file format specifications, and in all fonts derived from these that contain the characters, the glyph names are incorrectly spelled guillemotleft and guillemotright (a malapropism: guillemot is actually a species of seabird).

Microsoft use these punctuation marks to denote a mail merge "field", such as «Title», «AddressBlock» or «GreetingLine».

On the final printout, the guillemet-marked tags are replaced by each instance of the corresponding data item intended for that field by the user.

They were at 0xAE and 0xAF (174 and 175) in CP437 on the IBM PC, and 0xC7 and 0xC8 in Mac OS Roman, and placed in several of ISO 8859 code pages (namely: -1, -7, -8, -9, -13, -15, -16) at 0xAB and 0xBB (171 and 187).

Microsoft added the single guillemets to CP1252 and similar sets used in Windows at 0x8B and 0x9B (139 and 155) (where the ISO standard placed C1 control codes).