Here is a list of all documented files with brief descriptions:

[detail level 12]

toolbox
mexutils.h	MEX utilities
vl
aib.c	AIB - Definition
aib.h	AIB (Agglomerative Information Bottleneck (AIB))
array.h	Array
covdet.c	Covariant feature detectors - Definition
covdet.h	Covariant feature detectors (Covariant feature detectors)
dsift.c	Dense SIFT - Definition
dsift.h	Dense SIFT (Dense Scale Invariant Feature Transform (DSIFT))
fisher.c	Fisher - Declaration
fisher.h	Fisher encoding (Fisher Vector encoding (FV))
generic.c	Generic - Definition
generic.h	Generic (General support functionalities)
gmm.c	Gaussian Mixture Models - Implementation
gmm.h	GMM (Gaussian Mixture Models (GMM))
heap-def.h	Heap preprocessor metaprogram
hikmeans.c	Hierarchical Integer K-Means Clustering - Declaration
hikmeans.h	Hierarchical integer K-Means clustering
hog.c	Histogram of Oriented Gradients (HOG) - Definition
hog.h	Histogram of Oriented Gradients (Histogram of Oriented Gradients (HOG) features)
homkermap.c	Homogeneous kernel map - Definition
homkermap.h	Homogeneous kernel map (Homogeneous kernel map)
host.c	Host - Definition
host.h	Host
ikmeans.c	Integer K-Means clustering - Definition
ikmeans.h	Integer K-Means clustering
imopv.c	Vectorized image operations - Definition
imopv.h	Vectorized image operations
imopv_sse2.c	Vectorized image operations - SSE2 - Definition
imopv_sse2.h	Vectorized image operations - SSE2
kdtree.c	KD-tree - Definition
kdtree.h	KD-tree (KD-trees and forests)
kmeans.c	K-means - Declaration
kmeans.h	K-means (K-means clustering)
lbp.c	Local Binary Patterns (LBP) - Definition
lbp.h	Local Binary Patterns (LBP) descriptor (Local Binary Patterns (LBP) descriptor)
liop.c	Local Intensity Order Pattern (LIOP) descriptor - Definition
liop.h	Local Intensity Order Pattern (LIOP) descriptor (Local Intensity Order Pattern (LIOP) descriptor)
mathop.c	Math operations - Definition
mathop.h	Math operations (Mathematical operations)
mathop_avx.c	Mathop for AVX - Definition
mathop_avx.h	Mathop for avx
mathop_sse2.c	Mathop for SSE2 - Definition
mathop_sse2.h	Mathop for sse2
mser.c	MSER - Definition
mser.h	MSER (Maximally Stable Extremal Regions (MSER))
pgm.c	Portable graymap format (PGM) parser - Definition
pgm.h	Portable graymap format (PGM) parser
qsort-def.h	QSort preprocessor metaprogram
quickshift.c	Quick shift - Definition
quickshift.h	Quick shift (Quick shift image segmentation)
random.c	Random number generator - Definition
random.h	Random number generator (Random number generator)
rodrigues.c	Rodrigues formulas - Definition
rodrigues.h	Rodrigues formulas
scalespace.c	Scale Space - Definition
scalespace.h	Scale Space (Gaussian Scale Space (GSS))
shuffle-def.h	Shuffle preprocessor metaprogram
sift.c	SIFT - Definition
sift.h	SIFT (Scale Invariant Feature Transform (SIFT))
slic.c	SLIC superpixels - Definition
slic.h	SLIC superpixels (Simple Linear Iterative Clustering (SLIC))
stringop.c	String operations - Definition
stringop.h	String operations
svm.c	Support Vector Machines (SVM) - Implementation
svm.h	Support Vector Machines (Support Vector Machines (SVM))
svmdataset.c	SVM Dataset - Definition
svmdataset.h	SVM Dataset
vlad.c	VLAD - Declaration
vlad.h	VLAD encoding (Vector of Locally Aggregated Descriptors (VLAD) encoding)