diff --git a/BorgSansMono.fea b/BorgSansMono.fea
index 10a06268..1684625e 100644
--- a/BorgSansMono.fea
+++ b/BorgSansMono.fea
@@ -6,40 +6,40 @@ languagesystem kana dflt;
 
 feature calt {
   # /=
-  sub slash.equal equal' by space;
-  sub slash' equal by slash.equal;
+  sub slash_equal equal' by space;
+  sub slash' equal by slash_equal;
 
   # !==
-  sub exclam.equal.triple equal' equal by equal.triple.space;
-  sub exclam' equal equal by exclam.equal.triple;
+  sub exclam_equal_equal equal' equal by space.equal_triple;
+  sub exclam' equal equal by exclam_equal_equal;
 
   # ===
-  sub equal.triple.space equal' by space;
-  sub equal.triple equal' equal by equal.triple.space;
-  sub equal' equal equal by equal.triple;
+  sub space.equal_triple equal' by space;
+  sub equal_triple equal' equal by space.equal_triple;
+  sub equal' equal equal by equal_triple;
 
   # !=
   # must come after !==
-  sub exclam.equal equal' by space;
-  sub exclam' equal by exclam.equal;
+  sub exclam_equal equal' by space;
+  sub exclam' equal by exclam_equal;
 
   # ==
   # must come after != and /=
-  sub equal.equal equal' by space;
-  sub equal' equal by equal.equal;
+  sub equal_equal equal' by space;
+  sub equal' equal by equal_equal;
 
   # ->
-  sub arrow.right.thin greater' by space;
-  sub hyphen' greater by arrow.right.thin;
+  sub arrow_right_single greater' by space;
+  sub hyphen' greater by arrow_right_single;
 
   # <-
-  sub arrow.left.thin hyphen' by space;
-  sub less' hyphen by arrow.left.thin;
+  sub arrow_left_single hyphen' by space;
+  sub less' hyphen by arrow_left_single;
 
   # <=>
   ignore sub less equal' greater;
 
   # =>
-  sub arrow.right.fat greater' by space;
-  sub equal' greater by arrow.right.fat;
+  sub arrow_right_double greater' by space;
+  sub equal' greater by arrow_right_double;
 } calt;
diff --git a/BorgSansMono.sfdir/arrow.left.thin.glyph b/BorgSansMono.sfdir/arrow_left_single.glyph
similarity index 92%
rename from BorgSansMono.sfdir/arrow.left.thin.glyph
rename to BorgSansMono.sfdir/arrow_left_single.glyph
index ec22195a..f4c17b67 100644
--- a/BorgSansMono.sfdir/arrow.left.thin.glyph
+++ b/BorgSansMono.sfdir/arrow_left_single.glyph
@@ -1,4 +1,4 @@
-StartChar: arrow.left.thin
+StartChar: arrow_left_single
 Encoding: 65571 -1 906
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/arrow.right.fat.glyph b/BorgSansMono.sfdir/arrow_right_double.glyph
similarity index 94%
rename from BorgSansMono.sfdir/arrow.right.fat.glyph
rename to BorgSansMono.sfdir/arrow_right_double.glyph
index aa371b8e..ca01e9c5 100644
--- a/BorgSansMono.sfdir/arrow.right.fat.glyph
+++ b/BorgSansMono.sfdir/arrow_right_double.glyph
@@ -1,4 +1,4 @@
-StartChar: arrow.right.fat
+StartChar: arrow_right_double
 Encoding: 65564 -1 899
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/arrow.right.thin.glyph b/BorgSansMono.sfdir/arrow_right_single.glyph
similarity index 93%
rename from BorgSansMono.sfdir/arrow.right.thin.glyph
rename to BorgSansMono.sfdir/arrow_right_single.glyph
index b5a52653..fb946610 100644
--- a/BorgSansMono.sfdir/arrow.right.thin.glyph
+++ b/BorgSansMono.sfdir/arrow_right_single.glyph
@@ -1,4 +1,4 @@
-StartChar: arrow.right.thin
+StartChar: arrow_right_single
 Encoding: 65563 -1 898
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/equal.equal.glyph b/BorgSansMono.sfdir/equal_equal.glyph
similarity index 95%
rename from BorgSansMono.sfdir/equal.equal.glyph
rename to BorgSansMono.sfdir/equal_equal.glyph
index ef894ae9..be1a178f 100644
--- a/BorgSansMono.sfdir/equal.equal.glyph
+++ b/BorgSansMono.sfdir/equal_equal.glyph
@@ -1,4 +1,4 @@
-StartChar: equal.equal
+StartChar: equal_equal
 Encoding: 65567 -1 902
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/equal.triple.glyph b/BorgSansMono.sfdir/equal_triple.glyph
similarity index 97%
rename from BorgSansMono.sfdir/equal.triple.glyph
rename to BorgSansMono.sfdir/equal_triple.glyph
index cfbe1d30..ef1012f1 100644
--- a/BorgSansMono.sfdir/equal.triple.glyph
+++ b/BorgSansMono.sfdir/equal_triple.glyph
@@ -1,4 +1,4 @@
-StartChar: equal.triple
+StartChar: equal_triple
 Encoding: 65568 -1 903
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/exclam.equal.glyph b/BorgSansMono.sfdir/exclam_equal.glyph
similarity index 93%
rename from BorgSansMono.sfdir/exclam.equal.glyph
rename to BorgSansMono.sfdir/exclam_equal.glyph
index ae299ef4..887ffe0e 100644
--- a/BorgSansMono.sfdir/exclam.equal.glyph
+++ b/BorgSansMono.sfdir/exclam_equal.glyph
@@ -1,4 +1,4 @@
-StartChar: exclam.equal
+StartChar: exclam_equal
 Encoding: 65566 -1 901
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/exclam.equal.triple.glyph b/BorgSansMono.sfdir/exclam_equal_equal.glyph
similarity index 97%
rename from BorgSansMono.sfdir/exclam.equal.triple.glyph
rename to BorgSansMono.sfdir/exclam_equal_equal.glyph
index fde4103f..aeae131c 100644
--- a/BorgSansMono.sfdir/exclam.equal.triple.glyph
+++ b/BorgSansMono.sfdir/exclam_equal_equal.glyph
@@ -1,4 +1,4 @@
-StartChar: exclam.equal.triple
+StartChar: exclam_equal_equal
 Encoding: 65570 -1 905
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/slash.equal.glyph b/BorgSansMono.sfdir/slash_equal.glyph
similarity index 98%
rename from BorgSansMono.sfdir/slash.equal.glyph
rename to BorgSansMono.sfdir/slash_equal.glyph
index f81021f4..e155c4de 100644
--- a/BorgSansMono.sfdir/slash.equal.glyph
+++ b/BorgSansMono.sfdir/slash_equal.glyph
@@ -1,4 +1,4 @@
-StartChar: slash.equal
+StartChar: slash_equal
 Encoding: 65565 -1 900
 Width: 1229
 Flags: W
diff --git a/BorgSansMono.sfdir/equal.triple.space.glyph b/BorgSansMono.sfdir/space.equal_triple.glyph
similarity index 74%
rename from BorgSansMono.sfdir/equal.triple.space.glyph
rename to BorgSansMono.sfdir/space.equal_triple.glyph
index a15e2a7c..885ff336 100644
--- a/BorgSansMono.sfdir/equal.triple.space.glyph
+++ b/BorgSansMono.sfdir/space.equal_triple.glyph
@@ -1,4 +1,4 @@
-StartChar: equal.triple.space
+StartChar: space.equal_triple
 Encoding: 65569 -1 904
 Width: 1229
 Flags: W