  We present the STScI WFC3 project webpage, Transiting Exoplanets List of
Space Telescope Spectroscopy, TrExoLiSTS. It tabulates existing observations of
transiting exoplanet atmospheres, available in the MAST archive made with HST
WFC3 using the stare or spatial scan mode. A parallel page is available for all
instruments aboard JWST using the spectral Time Series Observation (TSO) mode.
The web pages include observations obtained during primary transits, secondary
eclipses and phase curves. TREXOLISTS facilitates proposal preparation for
programs that are highly-complementary to existing programs in terms of
targets, wavelength coverage, as well as reduces duplication and redundant
effort. Reference for the quality of the HST WFC3 visits taken more than 1.5
years ago are made available via including diagrams of the direct image, white
light curve and drift of the spectral time series across the detector. Future
improvements to the webpage will include: Expanding program query to other HST
instruments and reference for the quality of JWST visits.
