Configurable duplicate fields
This modifies Anki's duplicate checking in the editor so that additional fields can be used to check duplicates.

Fields to be checked can be set in Tools > Configurable Duplicate Fields > Config... (one field name per line).
Changes are saved to the add-on config and take effect immediately. No restart needed. The same settings can also be
edited by hand via the add-on's JSON config (Tools > Add-ons > Configurable duplicate fields > Config):
Replace example_field with the field name you want to check duplicates for. You can add multiple fields to check
duplicates for multiple fields. This way, duplicates can be compared between multiple decks, i.e., if Vocabulary-Kanji
in deck A has same value as target word in deck B, duplicate will be shown.

Exclude current note
By default, duplicate searches exclude the note being edited (exclude_own_note: true), matching Anki's own behavior.
If you prefer to see the original note next to its duplicates so you can compare them directly, untick
Exclude current note from duplicate search results in the configuration window (or set exclude_own_note to false).
Find Duplicates across your collection
Browse > Notes > (Configured Duplicates) Find duplicates... separate menu from Anki's built-in
Find Duplicates... scans the whole collection for notes that share the same value in any of the configured fields,
including values stored under differently named fields (e.g. Vocabulary-Kanji matching target word). Unlike the
built-in search, it checks all configured fields at once instead of one by one. An optional filter field (same search
syntax as the Browser, like Anki's own Find Duplicates filter) limits the scan to matching notes. Press Search or
Enter to re-run. Results are grouped by value and sorted by frequency; the report stays open next to the Browser, and
clicking a group (or Open All in Browser) shows the notes there so you can review them side by side, add tags etc.

Why?
Sometimes the first field in Anki is not the only field the user wants to check for duplicates. For example, when sentence mining,
using some automated system like mpvacious may only fill in the sentence, and the user
manually fills in the target word for the note. In this case, the user most likely wants to check the duplicate field for the target
word as well, to make sure they have not mined that word already.
How It Works
Configure the fields for duplicate checking in the add-on's configuration window.
When using this plugin, Anki will perform the same checks it is already doing on the first field,
but it will also search duplicates for the additional duplicate fields. When there is a duplicate,
the field is highlighted and a link for duplicates will be shown.
Notes
This plugin works only in Anki desktop, not in mobile.
This project is forked from https://github.com/matthayes/anki_flex_dupes although the functionality is completely different.