Discussion of Python in High Energy Physics https://hepsoftwarefoundation.org/activities/pyhep.html
Meanwhile, I think I've answered the question about Jupyter Notebooks: they seem to be exclusively Python. I can do searches through the API, though they're more rate-limited and I have to wait longer, so I have the gathering script print out results as it goes.
For each repo that GitHub labels as "Jupyter Notebook", I do two searches: one for the word "include" and the other for the word "import". If imports outnumber includes, I label it as Python. I've manually followed up a few cases with non-zero "includes"; they've all been in markdown cells.
FredStober/sandbox 0 vs 10 Python
michelif/bayesian_opt_skopt 0 vs 1 Python
michelif/HHbbgg_ETH 1 vs 18 Python
michelif/quickMLTests 0 vs 0 ???
terrenceedmonds/titanic 0 vs 2 Python
hbakhshi/Analysis13TeV 0 vs 0 ???
clint-richardson/BU-TheBus 0 vs 1 Python
clint-richardson/NBA-Data 0 vs 0 ???
clint-richardson/X53AnalysisDemo 0 vs 2 Python
zhangzc11/Pi0Net 0 vs 1 Python
joseph-taylor/LjLabBook 0 vs 5 Python
mukundvarma/kaggle-instacart 1 vs 2 Python
A-lxe/study-csc-daq-rate 0 vs 1 Python
vlimant/summer15-ArashJofrehei 0 vs 61 Python
vlimant/summer15-Irene 0 vs 12 Python
vlimant/summer15-MarinaKolosova 1 vs 45 Python
vlimant/summer15-SahandSeif 0 vs 25 Python
vlimant/summer16-NikolausHowe 0 vs 24 Python
vlimant/surf17-tutorial 0 vs 4 Python
vlimant/surf18-tutorial 0 vs 7 Python
davidlange6/gsocStudentSolutions 0 vs 3 Python
davidlange6/toy_notebooks 2 vs 14 Python
jbueghly/hzg_analysis 0 vs 5 Python
kaylanb/skinapp 0 vs 0 ???
kaylanb/thesis_code 0 vs 2 Python
lihux25/Projects 1 vs 3 Python
ArnabPurohit/Machine-Learning-applications-in-HEP 0 vs 1 Python
nhaubrich/biophysics 0 vs 8 Python
emc5ud/rosalind-solutions 1 vs 6 Python
nmehrle/echelle 0 vs 1 Python
zaixingmao/retina 1 vs 2 Python
fmanteca/ImageClassification 0 vs 1 Python
alkaplan/jupyter-notebooks 2 vs 6 Python
patrykel/multi-tracking-notebooks 0 vs 6 Python
patrykel/MultitrackingMasterProject 0 vs 2 Python
cfangmeier/HHC 0 vs 2 Python
cfangmeier/Small 1 vs 4 Python
cfangmeier/TTTT 0 vs 1 Python
cfangmeier/UNL-Gantry-Encapsulation-Monitoring 0 vs 2 Python
jiafulow/L1TMuonDocsNov2018 1 vs 1 ???
jiafulow/L1TMuonSimulationsMar2017 3 vs 18 Python
jiafulow/UF-slurm 0 vs 0 ???
monttj/computational-physics 1 vs 12 Python
NJManganelli/TaggerTest 0 vs 1 Python
sciencecw/cmsjupyter 1 vs 14 Python
lecriste/first-binder 0 vs 1 Python
mzanetti79/LaboratoryOfComputationalPhysics 0 vs 11 Python
mzanetti79/ML-INFN 2 vs 34 Python
mzanetti79/MLCC18 0 vs 23 Python
bpenning/jupyter_repo 0 vs 22 Python
bencammett/ML_project_Comp2 6 vs 12 Python
hbprosper/ENHEP 1 vs 8 Python
hbprosper/eshep_tutorials 0 vs 13 Python
Actually, in my slow-moving scan of Jupyter notebooks, I've finally come across two legitimate C++ Jupyter repos: https://github.com/gudrutis/jupyter-book-tutorials/search?utf8=%E2%9C%93&q=include&type= and https://github.com/javadebadi/learning_cpp_again/search?q=include&unscoped_q=include
These are the first 2 out of 91.
It would be very interesting to find out what the other collaborations are doing. I've looked into the GitLab API—it functions on gitlab.cern.ch, but I wasn't able to repeat any of these queries without figuring out its (different) authentication mechanism. And even then, I might have to be a member of a collaboration to see its users. If there's a culture of "in-development analysis is private, even from other members of the collaboration," then there might not be anything any one user can do to get a global picture.
Does anyone have any other suggestions? (GitHub preferred; I already have the scripts.)