Fixed

• Regenerate functions of regl-based traces in the "strict" bundle [#6141]

Added

• Add a CSP complaint variation of regl-based traces i.e. parcoords, splom, scattergl, scatterpolargl to the "strict" bundle [#6083]
• Add scattersmith trace to the "strict" bundle [#6135]

Fixed

• Fix mesh3d generation when alphahull is a positive number (regression introduced in 2.5.1) [#6133]

Added

• Add support to use version 3 of MathJax and add typesetMath attribute to config [#6073],
  with thanks to Equinor for sponsoring the related development!
• Add fillpattern options to scatter trace [#6101],
  with thanks to @s417-lama for the contribution!

Added

• Implement ticklabelstep to reduce labels on 2D axes and colorbars [#6088]

Changed

• Display the version of plotly.js when hovering over the modebar [#6077]
• Various dependency updates as listed under the v2.9.0 milestone

Fixed

• Fix vertical spacing of legend items in horizontal mode [#6094]

Fixed

• Correct formatted x/y texttempate for histogram trace [#6070]

Fixed

• Fix x/y texttemplate for histogram, bar, funnel and waterfall traces [#6069]

Fixed

• Do not exceed layout font size when textfont is set to "auto" for heatmap, histogram2d, contour and
  histogram2dcontour traces [#6061]

Added

• Introduce horizontal colorbars [#6024]
• Implement legend.grouptitlefont and hoverlabel.grouptitlefont [#6040]
• Add texttemplate and textfont to heatmap and histogram2d traces as well as
  histogram2dcontour and contour traces when coloring is set "heatmap" [#6028]

Fixed

• Fix to discard negative values from pie chart post-aggregation instead of during summation [#6051],
  with thanks to @destiny-wu for the contribution!

Added

• Add texttemplate, textposition, textfont, textangle,
  outsidetextfont, insidetextfont, insidetextanchor,
  constraintext and cliponaxis to histogram trace [#6038]

Changed

• Bump probe-image-size module to v7.2.2 [#6036]

Fixed

• Fix mapbox derived coordinate for Retina displays [#6039]
• Fix interaction between uirevision and autorange. Because we push autorange and range back into layout,
  there can be times it looks like we're applying GUI-driven changes on top of explicit autorange and other times
  it's an implicit autorange, even though the user's intent was always implicit. This fix treats them as equivalent. [#6046]