The sources were released in 2 episodes per file. I split them to match TheTVDB.com episode listing, so you'll have to resync any non-English language subs you download for the even numbered episodes. Use 00:05:42 for the split timecode (some even numbered episodes may have been split at 00:05:43; I didn't keep records on that).
How to split subs by timecode:
1. Download
MKVToolNix.
2. Open the GUI and drag your sub file into the input box.
3. Click on the Output tab.
4. Choose "After specific timecodes" for Split Mode.
5. Enter 00:05:42 in the box.
6. Optionally name the output file and press "Start muxing". It leaves you with a part 001 and part 002 file.
7. Discard the part 001 file and rename the part 002 to match the video filename. Place it in the same directory as the video file and play with a sub aware player such as vlc or mpc-hc (some players require it to be put in a subs subfolder).
Season: 1
Episode: 20
Title: Annoying Ex-Boydfriend
Summary: A boy bird named Boyd tries to win back his girlfriend through midnight serenade. A desperate-for-sleep Bugs realizes the only way to get him to stop... is to help.
Video: 1080p | x265 (H.265/HEVC) | CRF 22 | veryslow preset
Audio: English | AC-3 | 6 channels | 384 kbps (retained from source)
Subtitles (embedded SRT): English SDH
Source: Wabbit.S01E10.Wabbits.Best.Friend-Annoying.Ex.Boydfriend.1080p.WEB-DL.DD5.1.H.264-EsQ.mkv (5610 kbps)
Full media info:
General
Unique ID : 267813842396988346570004879854080243779 (0xC97B11E24DD8D5831C25CBDDE5EA3843)
Complete name : Wabbit S01E20 Annoying Ex-Boydfriend 1080p WebDL x265 HEVC 5.1 noobless[UTR].mkv
Format : Matroska
Format version : Version 4 / Version 2
File size : 62.9 MiB
Duration : 5mn 41s
Overall bit rate : 1 545 Kbps
Encoded date : UTC 2016-01-30 05:12:51
Writing application : mkvmerge v8.8.0 ('Wind at my back') 64bit
Writing library : Lavf57.11.100
DURATION : 00:05:19.125000000
NUMBER_OF_FRAMES : 117
NUMBER_OF_BYTES : 3150
_STATISTICS_WRITING_APP : mkvmerge v8.8.0 ('Wind at my back') 64bit
_STATISTICS_WRITING_DATE_UTC : 2016-01-30 05:12:51
_STATISTICS_TAGS : BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main@L5@Main
Codec ID : V_MPEGH/ISO/HEVC
Duration : 5mn 41s
Bit rate : 1 131 Kbps
Width : 1 916 pixels
Height : 1 076 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.023
Stream size : 46.0 MiB (73%)
Writing library : x265 1.8+60-6563218ce342:[Linux][GCC 4.9.3][64 bit] 8bit+10bit+12bit
Encoding settings : wpp / ctu=64 / min-cu-size=8 / max-tu-size=32 / tu-intra-depth=3 / tu-inter-depth=3 / me=3 / subme=4 / merange=57 / rect / amp / max-merge=4 / temporal-mvp / no-early-skip / rdpenalty=0 / no-tskip / no-tskip-fast / strong-intra-smoothing / no-lossless / no-cu-lossless / no-constrained-intra / no-fast-intra / open-gop / no-temporal-layers / interlace=0 / keyint=250 / min-keyint=23 / scenecut=40 / rc-lookahead=40 / lookahead-slices=0 / bframes=8 / bframe-bias=0 / b-adapt=2 / ref=5 / limit-refs=0 / weightp / weightb / aq-mode=1 / qg-size=32 / aq-strength=1.00 / cbqpoffs=0 / crqpoffs=0 / rd=6 / psy-rd=0.30 / rdoq-level=2 / psy-rdoq=1.00 / signhide / deblock / sao / no-sao-non-deblock / b-pyramid / cutree / no-intra-refresh / rc=crf / crf=22.0 / qcomp=0.60 / qpmin=0 / qpmax=51 / qpstep=4 / ipratio=1.40 / pbratio=1.30
Language : English
Default : Yes
Forced : No
DURATION : 00:05:41.300000000
NUMBER_OF_FRAMES : 8183
NUMBER_OF_BYTES : 49463995
_STATISTICS_WRITING_APP : mkvmerge v8.8.0 ('Wind at my back') 64bit
_STATISTICS_WRITING_DATE_UTC : 2016-01-30 05:12:51
_STATISTICS_TAGS : BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 5mn 41s
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Compression mode : Lossy
Delay relative to video : 31ms
Stream size : 15.6 MiB (25%)
Language : English
Default : Yes
Forced : No
Text
ID : 3
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Language : English
Default : Yes
Forced : No
Ignore the NUMBER_OF_FRAMES and NUMBER_OF_BYTES stats from mkvmerge in the global header; they are based on the last added track rather than the default video track.