(a) The TS map in 1.6–12.8 GeV constructed using standard background models. The 4FGL sources are marked by squares (for those with a “c” identifier) and crosses (for others). The position and size of 4FGL J1908.6+0915e, modeled by a uniform disk, are shown by a white dashed circle. LHAASO sub-PeV sources, modeled by a 2D Gaussian, are indicated by cyan dashed (WCDA) and solid (KM2A) circles. The position and size of HESS J1912+101, modeled by a spherical shell in H.E.S.S. Collaboration et al. (2018b), are shown by a yellow circle. (b) The same as panel (a), but in ≥12.8 GeV instead of 1.6–12.8 GeV. Three point sources to model the striped residual near LHAASO J1914+1150u are indicated by small pink circles. (c) The DNM template map (in arbitrary units) used to construct the standard diffuse model, which is internally available to the Fermi-LAT collaboration. (d) The same as panel (a), but when modeled with the additional ISM gas template and three point sources. (e) The same as panel (b), but when modeled with the additional ISM gas template and three point sources. A green circle at (l, b) ∼ (﹩44\mathop{.}\limits^{^\circ }5﹩, ﹩0\mathop{.}\limits^{^\circ }0﹩) indicates the small peak-like structure studied in Section 4.4.