Script - OP_PUSHDATAs
Little endian.

See, for example, the script_PushData unit test in the source tree that pushes one 0x5a byte onto the stack 4 different ways:

// Check that PUSHDATA1, PUSHDATA2, and PUSHDATA4 create the same value on                                                                
// the stack as the 1-75 opcodes do.                                                                                                      
static const unsigned char direct[] = { 1, 0x5a };
static const unsigned char pushdata1[] = { OP_PUSHDATA1, 1, 0x5a };
static const unsigned char pushdata2[] = { OP_PUSHDATA2, 1, 0, 0x5a };
static const unsigned char pushdata4[] = { OP_PUSHDATA4, 1, 0, 0, 0, 0x5a };