Roberts (1969; FBrf0020571) used "Dp(1;f)y[+]" to describe a class of aberrations recovered after irradiating X chromosomes carrying y[+] on the right arm. These chromosomes were recovered repeatedly in his screens. "Dp(1;f)y[+]" is really a generic category rather than the symbol for one specific chromosome, but it was listed in Lindsley and Zimm (FBrf0066905) as an aberration, so it's still in FlyBase as if it represents a unique chromosome.