diff --git a/extractions/README.md b/extractions/README.md
new file mode 100644
index 0000000..addf544
--- /dev/null
+++ b/extractions/README.md
@@ -0,0 +1,11 @@
+Extractions
+===========
+
+All the yosys extraction pass Verilog file used for mapping to the GAL
+structure. See the `synth_gal.tcl` file for details on how they're used. A
+summary is below (in the order they're used):
+
+- `ndff.v` merges NOT gates and DFFs into a single cell. Used to set the active
+  high/low state of the GAL_OLMCs later
+- `tristate.v` merges tristate cells and NOT gates or tristate cells and DFFs.
+  Used to combine tristate functionality into the GAL_OLMCs later
diff --git a/techmaps/README.md b/techmaps/README.md
index fb076f4..62c2de8 100644
--- a/techmaps/README.md
+++ b/techmaps/README.md
@@ -5,9 +5,13 @@ All the yosys techmapping libraries/Verilog files used for mapping to the GAL
 structure. See the `synth_gal.tcl` file for details on how they're used.
 A summary is below (in the order they're used):
 
+- `gal_dff.lib` Liberty library for supported FFs (only positive edge-triggered
+  DFFs). Used to prevent yosys from using fancy flip-flops
 - `pla.v` splits SOPs into a chain of SOPs with a specified size
 - `trivial_sop.v` replaces SOPs which are just buffers/NOT gates with
   buffer/NOT cells
+- `olmc_seq.v` converts all existing sequential elements into GAL_OLMCs this
+  includes special merged types from other techmap passes/extractions
 - `one_sop.v` converts GAL_SOPs with only one product into GAL_1SOPs. Used on
   enabled (tristate) lines
 - `pla_olmc_int.v` adds a combinational GAL_OLMC after a GAL_SOP. Used to