Eri worked on the Esri/harfbuzz repository, focusing on improving mathematical typesetting by addressing a bug in OpenType MATH font metrics for Cambria Math. Using C++ and expertise in font metrics and the OpenType MATH table, Eri corrected the scaling logic that determines minimum heights for display operators and delimited sub-formulas. This fix ensures that Cambria Math fonts are interpreted accurately, leading to more consistent and predictable math layout across platforms. The work involved targeted validation of font metrics and alignment with HarfBuzz’s handling practices, resulting in more stable rendering and reducing defects in mathematical typesetting scenarios.