diff --git a/MarathonData.md b/MarathonData.md
index c505b65..ecab614 100644
--- a/MarathonData.md
+++ b/MarathonData.md
@@ -957,7 +957,7 @@ Static Map Info is 88 bytes.
 | ----           | ----       | ------ |
 | `EnvCode`      | `u16`      | `0`    |
 | `PhysicsId`    | `u16`      | `2`    |
-| `MusicId`      | `u16`      | `4`    |
+| `LandscapeId`  | `u16`      | `4`    |
 | `MissionFlags` | `u16`      | `6`    |
 | `EnvFlags`     | `u16`      | `8`    |
 | `Name`         | `u8[66]`   | `18`   |
@@ -965,6 +965,14 @@ Static Map Info is 88 bytes.
 
 - `EnvCode` is a preset number for texture collections and some other things
 such as media (liquid) presets.
+- `PhysicsId` used to be used for specifying three physics models: one for the
+Forge editor, one for the game, and one for low-gravity. However, the first one
+ended up being useless and the third was made into a map flag instead which
+simply modifies the current physics model. This should always be set to `1` by
+new editors.
+- `LandscapeId` is the landscape number to use for the sky. This starts at `0`,
+since it's an offset into the landscape collections. If `DataVersion` is
+`DataM1`, then this is used as the music index instead.
 - `MissionFlags` is a Mission Flags bit field.
 - `EnvFlags` is an Environment Flags bit field.
 - `Name` is the level name, intended to be 65 bytes, but one padding byte is
diff --git a/source/leela/main.rs b/source/leela/main.rs
index 672442e..ecf4bda 100644
--- a/source/leela/main.rs
+++ b/source/leela/main.rs
@@ -193,11 +193,6 @@ fn main() -> ResultS<()>
            StoreTrue,
            "wad: Dump all known chunks");
 
-      arg!("--wad-dump-unknown",
-           opt.wad_unknown,
-           StoreTrue,
-           "wad: Dump all unknown chunks");
-
       arg!("--wad-write-header",
            opt.wad_header,
            StoreTrue,
@@ -261,7 +256,6 @@ struct Options
    shp_seq:     bool,
    snd_dump:    bool,
    snd_write:   bool,
-   wad_unknown: bool,
    wad_wrt_all: bool,
    wad_header:  bool,
 }
diff --git a/source/marathon/map.rs b/source/marathon/map.rs
index e7c3344..d1d2955 100644
--- a/source/marathon/map.rs
+++ b/source/marathon/map.rs
@@ -50,9 +50,9 @@ pub fn read_minf(b: &[u8]) -> ResultS<Minf>
 {
    read_data! {
       88, BE in b =>
-      env_code    = u16[0];
-      physi_id    = u16[2];
-      music_id    = u16[4];
+      texture_id  = u16[0];
+      physics_id  = u16[2];
+      skypict_id  = u16[4];
       missi_flags = u16[6];
       envir_flags = u16[8];
       level_name  = mac_roman_cstr[18..84];
@@ -63,8 +63,8 @@ pub fn read_minf(b: &[u8]) -> ResultS<Minf>
    let envir_flags = flag_ok!(EnvFlags, envir_flags)?;
    let entry_flags = flag_ok!(EntFlags, entry_flags)?;
 
-   Ok(Minf{env_code, physi_id, music_id, missi_flags, envir_flags, entry_flags,
-           level_name})
+   Ok(Minf{texture_id, physics_id, skypict_id, missi_flags, envir_flags,
+           entry_flags, level_name})
 }
 
 /// Reads an old `Minf` chunk.
@@ -495,8 +495,22 @@ impl Default for PolyType
    fn default() -> Self {PolyType::Normal}
 }
 
+impl Default for Minf
+{
+   fn default() -> Self
+   {
+      Minf{texture_id:  0,
+           physics_id:  1,
+           skypict_id:  0,
+           missi_flags: MsnFlags::empty(),
+           envir_flags: EnvFlags::empty(),
+           entry_flags: EntFlags::Solo,
+           level_name:  "Map".to_string()}
+   }
+}
+
 /// A point in world-space.
-#[derive(Clone, Default, PartialEq, serde::Serialize)]
+#[derive(Clone, Debug, Default, PartialEq, serde::Serialize)]
 pub struct Point
 {
    pub x: Unit,
@@ -683,12 +697,12 @@ pub struct Note
 }
 
 /// Static map information.
-#[derive(Debug, Default, PartialEq, serde::Serialize)]
+#[derive(Debug, PartialEq, serde::Serialize)]
 pub struct Minf
 {
-   pub env_code:    u16,
-   pub physi_id:    u16,
-   pub music_id:    u16,
+   pub texture_id:  u16,
+   pub physics_id:  u16,
+   pub skypict_id:  u16,
    pub missi_flags: MsnFlags,
    pub envir_flags: EnvFlags,
    pub entry_flags: EntFlags,
@@ -757,7 +771,7 @@ bitflags! {
 
 bitflags! {
    /// Static environment flags.
-   #[derive(Default, serde::Serialize)]
+   #[derive(serde::Serialize)]
    pub struct EnvFlags: u16
    {
       const Vacuum     = 1;
@@ -776,7 +790,7 @@ bitflags! {
 
 bitflags! {
    /// Static entry point flags.
-   #[derive(Default, serde::Serialize)]
+   #[derive(serde::Serialize)]
    pub struct EntFlags: u32
    {
       const Solo    = 1;
@@ -792,7 +806,7 @@ bitflags! {
 
 bitflags! {
    /// Static mission flags.
-   #[derive(Default, serde::Serialize)]
+   #[derive(serde::Serialize)]
    pub struct MsnFlags: u16
    {
       const Extermination = 1;
@@ -922,14 +936,6 @@ c_enum! {
    }
 }
 
-impl std::fmt::Debug for Point
-{
-   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
-   {
-      write!(f, "({}, {})", self.x, self.y)
-   }
-}
-
 pub const TICKS_PER_SECOND: u16 = 30;
 
 const OLD_LIGHT_DEFINITIONS: [Light; 8] = [