diff --git a/gridinfo/.gitignore b/gridinfo/.gitignore
index 4af748d9..13eda629 100644
--- a/gridinfo/.gitignore
+++ b/gridinfo/.gitignore
@@ -9,3 +9,4 @@
 /logicframes_SLICE_*.asc
 /grid-*-db.txt
 /grid-*-db.json
+/grid-*-db.html
diff --git a/gridinfo/README b/gridinfo/README
new file mode 100644
index 00000000..463a01e7
--- /dev/null
+++ b/gridinfo/README
@@ -0,0 +1,7 @@
+
+Cached database for xc7a50tfgg484-1:
+
+http://scratch.clifford.at/prjxray/grid-xc7a50tfgg484-1-db.html
+http://scratch.clifford.at/prjxray/grid-xc7a50tfgg484-1-db.json
+http://scratch.clifford.at/prjxray/grid-xc7a50tfgg484-1-db.txt
+