compression.md

+Transparent stream compression is always optional. Compressed data is recognized by the four-byte magic value `1 76 79 66`.
+
+```c
+struct am2lob {
+  uint8_t magic[4];    // {0x01, 0x4C, 0x4F, 0x42} ("\1LOB")
+  uint8_t method;      // has to be 6 for Ambermoon
+  uint8_t rawSize[3];  // big-endian size of uncompressed data
+  uint8_t cmpSize[4];  // big-endian size of compressed data
+  uint8_t cmpData[cmpSize];
+};
+```
+
+TODO: document decompression algorithm and in-place decompression issues.
+
+Trivia: LOB = [Lothar Becks](https://www.mobygames.com/developer/sheet/view/developerId,177857/)
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