Recent work suggests doxycycline can help with tendon and cartilage repair. For example, see:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7752016/
or

https://drrobertlaprademd.com/wp-content/uploads/2020/05/Doxycycline-improves-tendon-and-cartilage-pathologies.pdf

There's also a phase 1 clinical trial in progress to assess the use of doxycycline for elbow tendinopathy: https://www.clinicaltrials.gov/study/NCT04686799?term=NCT04686799&rank=1

If before 2034 I find significant evidence that doxcycline is a common treatment for repetitive strain injuries, I will resolve this to YES.

Significant evidence could include the Mayo Clinic or WebMD pages for RSI and related conditions (like wrist pain or tennis elbow). Other potential sources of evidence include review papers or mainstream media articles.