This is a simple clone of what is found at:
https://sourceforge.net/projects/bashdb/files/bashdb/5.0-1.1.2/
a Sourceforge repo that has been stagnant since 2019. It had two identical broken links to documentation as follows:
tree-structured reference manual
The last snapshot of that was found on the Way Back Machine dated October 26, 2018 and saved here as manual.html
For now not a finger more has been lifted on this, it has not been tried, tested or otherwise explored simply transferred to a GitHub repo for now with the last copy of it's manual.
As time permits will take a look at it, but in the mean time, anyone else can too, and it's a more visible location I suspect.
Worth noting that there are, at time of transfer here, 9 open bugs on Sourceforge
https://sourceforge.net/p/bashdb/bugs/
dating from 2016 to 2021.
Clearly this could yous a champion to manage and maintain it.