Combining the dictionaries utilized by the above sources results in the following list:
To download most of the dictionaries above, one could, for example, use the following text file with aria2:
# JMdict/EDICT ftp://ftp.edrdg.org/pub/Nihongo/JMdict http://ftp.edrdg.org/pub/Nihongo/JMdict ftp://ftp.edrdg.org/pub/Nihongo/JMdict_e http://ftp.edrdg.org/pub/Nihongo/JMdict_e ftp://ftp.edrdg.org/pub/Nihongo/JMdict_e_examp http://ftp.edrdg.org/pub/Nihongo/JMdict_e_examp ftp://ftp.edrdg.org/pub/Nihongo/edict http://ftp.edrdg.org/pub/Nihongo/edict ftp://ftp.edrdg.org/pub/Nihongo/edict2 http://ftp.edrdg.org/pub/Nihongo/edict2 # ENAMDICT/JMnedict ftp://ftp.edrdg.org/pub/Nihongo/enamdict http://ftp.edrdg.org/pub/Nihongo/enamdict ftp://ftp.edrdg.org/pub/Nihongo/JMnedict.xml http://ftp.edrdg.org/pub/Nihongo/JMnedict.xml # KANJIDIC ftp://ftp.edrdg.org/pub/Nihongo/kanjidic2.xml http://ftp.edrdg.org/pub/Nihongo/kanjidic2.xml ftp://ftp.edrdg.org/pub/Nihongo/kanjidic http://ftp.edrdg.org/pub/Nihongo/kanjidic ftp://ftp.edrdg.org/pub/Nihongo/kanjd212 http://ftp.edrdg.org/pub/Nihongo/kanjd212 # Kanjium https://github.com/mifunetoshiro/kanjium/raw/master/data/kanjidb.sqlite # Rikaichan https://www.polarcloud.com/down/mdo/rikaichan-nl-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-en-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-fr-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-de-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-hu-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-ru-2-01-211001.xpi https://www.polarcloud.com/down/mdo/rikaichan-names-2-01-211001.xpi
This will just grab the “most important” files, i. e. the ones listed as download links on the respective pages. More files from the EDRDG are listed here.
JMdict is available in three formats. More information can be found here, but in short:
JMnedict uses a similar format to JMdict, with details available under the “Format” section here.
The format used by KANJIDIC is documented on its page as well.
RikaiCake serves its entire database via two HTML tables here, though DataTables is used to make it more accessible. To download it, grabbing the source code of that page is recommended – there doesn’t seem to be any other method at the moment.
Yomichan also provides downloads of a lot of the aforementioned dictionaries, preprocessed into a simple JSON format, though these may be out of date due to being unofficial.
Due to EPWING being a proprietary format, not much is known about it. However, its Wikipedia page provides a few details about the various specifications (EPWING V1 through V6, as well as EPWING ST). It should be noted that EPWING dictionaries are not stored in a single file, but rather a directory tree.
Wadoku makes its database available as an XML dump, which includes an XML schema (.XSD), as well as an EDICT2 file. A (presumably third-party) EPWING-compatible dump can be found at OSDN.
Huge thanks to everyone involved with the above dictionaries and sources, especially the Electronic Dictionary Research and Development Group.