generic BMP PUA, code page 1445 (IBM AFP PUA No. 1) for plane 15 with IBM allocations in U+FFF00–U+FFFFD, and code page 1449 (IBM default PUA) for the BMP PUA with IBM allocations in U+F83D–U+F8FF. The file system found in Windows uses the U+F000 to U+F0FF block to escape special characters. NetApp translates characters in filenames that are allowed on Unix but invalid for SMB clients to PUA characters. Twitter's Chirp font provides some additional icons, like U+E000 which corresponds to a left down arrow, U+EA00 which corresponds to the Twitter bird, and U+F8FF which corresponds to an Apple logo, possibly for compatibility with Apple fonts. Private-use characters in other character sets The concept of reserving specific code points for Private Use is based on similar earlier usage in other character sets. In particular, many otherwise obsolete characters in East Asian scripts continue to be used in specific names or other situations, and so some character sets for those scripts made allowance for private-use characters (such as the user-defined planes of CNS 11643, or gaiji in certain Japanese encodings). The Unicode standard references these uses under the name "End User Character Definition" (EUCD). Additionally, the C1 control block contains two codes intended for private use "control functions" by ECMA-48: 0x91 (PU1) and 0x92 (PU2). Unicode includes these at and but defines them as control characters (category Cc), not private-use characters (category Co). Encodings which do not have private use areas but have more or less unused areas, such as ISO/IEC 8859 and Shift JIS, have seen uncontrolled variants of these encodings evolve. For Unicode, software companies can use the Private Use Areas for their desired additions. Notes References Articles with unsupported PUA characters