• There are 47 files with units, with 8,616 lines of code.
• 0 very complex files (McCabe index sum 251+; 0 lines of code)
• 2 complex files (McCabe index sum 126-250; 2,072 lines of code)
• 5 medium complex files (McCabe index sum 51-125; 2,006 lines of code)
• 12 slightly complex files (McCabe index sum 26-50; 2,584 lines of code)
• 28 simple files (McCabe index sum 1-25; 1,954 lines of code)
• 3 main files have no units (e.g. languages without unit analysis, or files without functions) and are not classified.

The McCabe index of a file grows with its size: per 100 lines tells a large but plain file from a dense one, and most complex unit whether the complexity sits in one unit or is spread over many.

File	# lines	# units	McCabe index (sum)	per 100 lines	most complex unit
s3.go in storage	1151	42	224	19	19
cp.go in command	921	24	145	16	28
url.go in storage/url	320	28	77	24	12
sync.go in command	453	10	69	15	17
token_manager.go in storage	322	18	68	21	15
bench.py in benchmark	467	26	66	14	11
ant_bench.py in bench	444	17	62	14	16
fs.go in storage	207	16	46	22	7
select.go in command	365	6	38	10	17
auto_complete.go in command	183	8	36	20	7
rm.go in command	231	4	35	15	15
flag.go in command	132	17	31	23	5
ls.go in command	270	7	31	11	7
pipe.go in command	285	8	31	11	8
storage.go in storage	194	19	28	14	4
log.go in log	118	14	28	24	6
run.go in command	179	8	28	16	11
stat.go in command	201	6	28	14	11
du.go in command	219	7	27	12	10
validation.go in command	55	4	22	40	10
context.go in command	85	3	21	25	9
message.go in log	88	10	20	23	6
useragent.go in useragent	106	3	18	17	10
cat.go in command	132	3	15	11	8
expand.go in command	72	2	15	21	8
stat.go in log/stat	85	6	14	16	4
presign.go in command	110	3	14	13	8
wildcard.go in command	51	3	14	27	5
orderedwriter.go in orderedwriter	80	2	13	16	12
progressbar.go in progressbar	58	13	13	22	1
bucket_version.go in command	128	4	12	9	5
error.go in error	58	5	12	21	7
parallel.go in parallel	64	8	11	17	3
mb.go in command	100	3	11	11	4
strutil.go in strutil	56	6	10	18	4
error.go in command	77	3	10	13	6
notifier.go in storage	51	3	9	18	7
sync_strategy.go in command	33	3	7	21	3
rb.go in command	74	2	6	8	4
app.go in command	253	4	6	2	3
global.go in parallel	13	3	4	31	2
fdlimit_unix.go in parallel/fdlimit	22	1	4	18	4
main.go in root	21	1	3	14	3
version.go in version	13	1	2	15	2
mv.go in command	50	1	2	4	2
fdlimit_windows.go in parallel/fdlimit	2	1	1	50	1
version.go in command	17	1	1	6	1

• File complexity is the sum of the McCabe indexes (conditional complexity) of the units (methods, functions...) in a file.
• Files are classified in five categories based on that sum: 1-25 (simple files), 26-50 (slightly complex files), 51-125 (medium complex files), 126-250 (complex files), 251+ (very complex files). The default bands are five times the unit complexity bands, as a file is a group of units.
• Only main code files with units are classified. Files without units (languages without unit analysis, or files without functions) have no complexity to measure and are left out rather than counted as simple.
• A very complex file holds many decisions, which often means it has too many responsibilities: a candidate to split, and a place where changes need more testing.