diff --git a/Cargo.toml b/Cargo.toml
index 35d4339..ac9d24c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-default = []
+default = ["mapped-file"]
 
 unstable = ["parking_lot?/nightly", "memchr/compiler_builtins", "crossbeam-queue?/nightly", "futures?/unstable", "color-eyre/track-caller"]
 
@@ -32,9 +32,7 @@ threads-async = ["threads", "dep:futures", "dep:tokio-uring", "dep:tokio-stream"
 
 #XXX ["output-lines", "buffer-output", "ignore-output-errors", "ignore-invalid-args"]
 
-#TODO: Branch repo, and begin refactor:
-#
-#TODO: Move these features to Clap runtime arg parse options; Major refactor, bump to 0.5.0 or to 1.0.0[r0]
+#TODO: Move these features to Clap runtime arg parse options.
 
 #TODO: Add feature 'mapped-file': Attempt to map input file and process data backwards from end if possible.
 #TODO: Add feature 'threads': Use rayon to parallelise line-searching in buffer (or mapped file ^) (partition in half, move partition line to closest {r,}memchr('\n'); repeat N times recursively on each side (parallel) where N is number of logical CPU cores and/or to get the chunks below/in a certain size range. 
diff --git a/src/main.rs b/src/main.rs
index 53b824c..144838a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,6 @@
 
+mod part;
+
 //#[inline] 
 fn reverse<T>(slice: &mut [T])
 {
diff --git a/src/part.rs b/src/part.rs
new file mode 100644
index 0000000..d003187
--- /dev/null
+++ b/src/part.rs
@@ -0,0 +1,3 @@
+//! Partitioning even areas by delimitor byte.
+use super::*;
+