diff --git a/lz16/README.md b/lz16/README.md
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+# LZ16 - simple compressed file format
+
+LZ16 provides a simple format for reading and writing LZSS-compressed files on memory-contained systems.
+
+## File format
+
+LZ16 files start with a 4 byte header, reading "lz16".
+
+This is followed by an arbitrary number of blocks in the format:
+
+ - 2 bytes compressed data length
+ - the compressed data
+
+This is terminated either by a zero-length block, or the end of the file.
diff --git a/mtar/README.md b/mtar/README.md
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+# mtar - Minitel Archiver
+
+mtar is a file format for storing multiple files in a single file, much like tar, cpio or zip.
+
+## File format
+
+mtar archive files consist of a number of file entries, in the following format:
+
+- 2 bytes file name length
+- the file name
+- 2 bytes file content length
+- the file contents
+
+Archives are terminated either by the end of file, or a record with a name length of zero.