Open-source, free WordPress themes for technology blogs:

Here are some popular open-source, free WordPress themes for technology blogs:

1. Astra: This theme is lightweight, customizable, and optimized for speed, which are all important factors for SEO. Astra is a free theme, but it also has a paid version that offers more features and customization options.
2. GeneratePress: This theme is also lightweight and fast, and it has a variety of customization options and built-in schema markup. GeneratePress is a free theme with a premium version that offers more features.
3. Neve: This theme is designed to be lightweight, fast, and responsive, and it’s optimized for SEO and page speed. It also offers compatibility with popular SEO plugins. Neve is free and has a pro version with more features.
4. Schema Lite: This theme is designed specifically for blogs, it is lightweight and fast, and it includes built-in schema markup for better SEO. This theme is completely free.
5. OceanWP: This theme is lightweight, customizable, and optimized for speed, and it includes built-in schema markup and integration with popular SEO plugins like Yoast. OceanWP is free and also has a paid version with more features.
6. Writee: It’s a clean, minimal, and responsive WordPress theme, it has powerful theme options, and custom widgets, and it’s SEO friendly.

Note that even though these themes are free, some of them may still require payment for some advanced features or support.