Dear Dominik and all,

The sign that you are referring to is widely used already in the oldest dated manuscript that we are using for digital critical edition of the Nyāyabhāṣya in Leipzig, a paper manuscript from Jaisalmer in Devanagari, datable to 1222. We decided to transcribe it as a hyphen (-), since it is mostly (though not exclusively) used to separate akṣaras within a word at the end of the line and before virtual string holes. The hyphen sign suggested itself to us intuitively, because its usage in the manuscript corresponds roughly to the usage of a hyphen in our modern practice of writing in Latin script. In the case of this manuscript, the interpretation of this sign as a line filler is not the most obvious choice, because the sign is used frequently in cases where the line would already be filled completely without the use of this special sign, like here: 

Quite frequently, when the end of the line coincides with the end of a word,  the scribe left some space without using the hyphenation sign :

I have not fully investigate the matter, because it is not of central importance for the creation of the documentation of variant readings in our project (not to speak of the critical edition), but apparently the scribe was not absolutely consistent in his usage of this sign.

With best wishes,

Philipp