Data and timing-model analysis for: Large Transit-timing Variations in the 49.7 day Transit Candidate TIC 300164137

Code, data, and results for the Research Note "Large Transit-timing Variations in the 49.7 day Transit Candidate TIC 300164137" (S. Bai 2026, Research Notes of the AAS). TIC300164137_TTV_analysis_v2.zip: the sixteen TESS mid-transit times (BJD_TDB - 2457000), polynomial ephemerides, coplanar two-companion TTVFast timing fits in period-ratio bins, finite-time MEGNO screening with REBOUND from TTVFast-consistent initial states, a TTVFast/IAS15 integrator check, a restricted stellar-perturber search, an exploratory residual light-curve search, and the figure with its data tables. TIC300164137_upstream_{core,lightcurves,injections,shape_localization_ltte}_v2.zip (four parts that unzip into one folder): the observation-side analysis for this target as run - original QLP and TESS-SPOC light curves with a product inventory and hashes, all fitted event windows with exclusion codes, per-event timing and uncertainty estimates, injection-recovery tests, the limb-darkened shape fit, the secondary-eclipse scan, difference-image and PRF localization, the pure light-travel-time test, scripts, and method notes. Changes from v1: all REBOUND entry points now use the TTVFast-consistent initial state (the revision-1 set-up is kept in legacy/); the integrator agreement is documented at the adopted timestep (within 17.4 s for six representative solutions); integration lengths are stated in units of the transiting body's period; and the upstream analysis is added. The dynamical fits are timing-only examples from a finite search; they are not posterior distributions, mass measurements, or a census of long-term-stable architectures, and the epoch-61 model range is not a confidence interval. QLP light curves: doi:10.17909/t9-r086-e880 (Huang et al. 2020a,b; Kunimoto et al. 2021, 2022), obtained from MAST.