MetaProxy is an open source freeware program that allows archival descriptions, search terms, provenance, and any other meta-data (i.e. data about data) to be associated with images and other file types. In short, it's like being able to write notes on the back of any document and search for it by tags or key phrases. So; it would likely interest those doing transcriptions as well as those wanting to keep research notes on what they've found.
There are currently versions for both Mac and Windows.

In photography, it is common practice to embed information about the image within the file itself. This has a number of drawbacks, but three key ones are particularly worth of note;
• Many people prefer not to alter their original photographs or other documents in any way
• The embedded data is often accessible only via specialized software
• Not all file formats permit the embedding of metadata

To combat the first item, the concept of “sidecar” files was conceived. A sidecar is a second file that is colocated with the master document and contains the metadata information. However; the vast majority of sidecar file formats still suffer from requiring specialized software to read and write them. And; they still tend not to be available for use with all file formats.

MetaProxy builds on the sidecar concept, by using a “buddy file”. This is nothing more than a sidecar file in the form of a text file with a unique file extension (i.e. the part of the filename to the right of the “.”). The use of a text file means that no specialized software is needed to read and write them. The text editor, already present on your Apple computer, is completely adequate for the task. Furthermore, MetaProxy has been designed to permit associating a buddy file with nearly any file for which it makes sense to do so.

Associating a buddy file is as simple as ensuring that the buddy file shares the same name (i.e. the part of the filename to the left of the “.”) as the file or files for which it is to contain information, but has a unique extension (i.e. the part of the filename to the right of the “.”)

MetaProxy makes use of a few common features of current operating systems. Almost without exception, one can;
• search the contents of the computer for files containing a unique identifier, called a “tag”
• Execute a program by clicking on one of its data files

The name of a tag is something which is totally up to you. That said, MetaProxy also has the unique capability to help you to create buddy files by having you select one of the documents for which one is to be created.

MetaProxy uses the default tag, “#NewMetaDataFile”, when it creates one on your behalf. However; the extension of a buddy file is how the computer knows to use MetaProxy and not some other application. So, it must be unique. By default, MetaProxy uses the extension “meta”, but this can be changed if desired.

There is a write-up on Tony Proctor's blog at:
https://parallax-viewpoint.blogspot....mJpGhjDLkZMH08

You can also read more about it and find the links to the software itself on the Facebook group:
https://www.facebook.com/groups/541621946332678/